diff --git a/backend/src/main/java/com/printcalculator/controller/CustomQuoteRequestController.java b/backend/src/main/java/com/printcalculator/controller/CustomQuoteRequestController.java
index 003ade8..908ef71 100644
--- a/backend/src/main/java/com/printcalculator/controller/CustomQuoteRequestController.java
+++ b/backend/src/main/java/com/printcalculator/controller/CustomQuoteRequestController.java
@@ -5,7 +5,7 @@ import com.printcalculator.entity.CustomQuoteRequest;
 import com.printcalculator.entity.CustomQuoteRequestAttachment;
 import com.printcalculator.repository.CustomQuoteRequestAttachmentRepository;
 import com.printcalculator.repository.CustomQuoteRequestRepository;
-import com.printcalculator.service.ClamAVService;
+import com.printcalculator.service.storage.ClamAVService;
 import com.printcalculator.service.email.EmailNotificationService;
 import jakarta.validation.Valid;
 import org.slf4j.Logger;
diff --git a/backend/src/main/java/com/printcalculator/controller/OptionsController.java b/backend/src/main/java/com/printcalculator/controller/OptionsController.java
index e187422..56cd26b 100644
--- a/backend/src/main/java/com/printcalculator/controller/OptionsController.java
+++ b/backend/src/main/java/com/printcalculator/controller/OptionsController.java
@@ -3,17 +3,16 @@ package com.printcalculator.controller;
 import com.printcalculator.dto.OptionsResponse;
 import com.printcalculator.entity.FilamentMaterialType;
 import com.printcalculator.entity.FilamentVariant;
-import com.printcalculator.entity.LayerHeightOption;
 import com.printcalculator.entity.MaterialOrcaProfileMap;
 import com.printcalculator.entity.NozzleOption;
 import com.printcalculator.entity.PrinterMachine;
 import com.printcalculator.entity.PrinterMachineProfile;
 import com.printcalculator.repository.FilamentMaterialTypeRepository;
 import com.printcalculator.repository.FilamentVariantRepository;
-import com.printcalculator.repository.LayerHeightOptionRepository;
 import com.printcalculator.repository.MaterialOrcaProfileMapRepository;
 import com.printcalculator.repository.NozzleOptionRepository;
 import com.printcalculator.repository.PrinterMachineRepository;
+import com.printcalculator.service.NozzleLayerHeightPolicyService;
 import com.printcalculator.service.OrcaProfileResolver;
 import org.springframework.http.ResponseEntity;
 import org.springframework.transaction.annotation.Transactional;
@@ -24,6 +23,7 @@ import org.springframework.web.bind.annotation.RestController;
 import java.math.BigDecimal;
 import java.util.Comparator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -32,26 +32,26 @@ public class OptionsController {
 
     private final FilamentMaterialTypeRepository materialRepo;
     private final FilamentVariantRepository variantRepo;
-    private final LayerHeightOptionRepository layerHeightRepo;
     private final NozzleOptionRepository nozzleRepo;
     private final PrinterMachineRepository printerMachineRepo;
     private final MaterialOrcaProfileMapRepository materialOrcaMapRepo;
     private final OrcaProfileResolver orcaProfileResolver;
+    private final NozzleLayerHeightPolicyService nozzleLayerHeightPolicyService;
 
     public OptionsController(FilamentMaterialTypeRepository materialRepo,
                              FilamentVariantRepository variantRepo,
-                             LayerHeightOptionRepository layerHeightRepo,
                              NozzleOptionRepository nozzleRepo,
                              PrinterMachineRepository printerMachineRepo,
                              MaterialOrcaProfileMapRepository materialOrcaMapRepo,
-                             OrcaProfileResolver orcaProfileResolver) {
+                             OrcaProfileResolver orcaProfileResolver,
+                             NozzleLayerHeightPolicyService nozzleLayerHeightPolicyService) {
         this.materialRepo = materialRepo;
         this.variantRepo = variantRepo;
-        this.layerHeightRepo = layerHeightRepo;
         this.nozzleRepo = nozzleRepo;
         this.printerMachineRepo = printerMachineRepo;
         this.materialOrcaMapRepo = materialOrcaMapRepo;
         this.orcaProfileResolver = orcaProfileResolver;
+        this.nozzleLayerHeightPolicyService = nozzleLayerHeightPolicyService;
     }
 
     @GetMapping("/api/calculator/options")
@@ -116,15 +116,6 @@ public class OptionsController {
                 new OptionsResponse.InfillPatternOption("cubic", "Cubic")
         );
 
-        List<OptionsResponse.LayerHeightOptionDTO> layers = layerHeightRepo.findAll().stream()
-                .filter(l -> Boolean.TRUE.equals(l.getIsActive()))
-                .sorted(Comparator.comparing(LayerHeightOption::getLayerHeightMm))
-                .map(l -> new OptionsResponse.LayerHeightOptionDTO(
-                        l.getLayerHeightMm().doubleValue(),
-                        String.format("%.2f mm", l.getLayerHeightMm())
-                ))
-                .toList();
-
         List<OptionsResponse.NozzleOptionDTO> nozzles = nozzleRepo.findAll().stream()
                 .filter(n -> Boolean.TRUE.equals(n.getIsActive()))
                 .sorted(Comparator.comparing(NozzleOption::getNozzleDiameterMm))
@@ -137,7 +128,31 @@ public class OptionsController {
                 ))
                 .toList();
 
-        return ResponseEntity.ok(new OptionsResponse(materialOptions, qualities, patterns, layers, nozzles));
+        Map<BigDecimal, List<BigDecimal>> rulesByNozzle = nozzleLayerHeightPolicyService.getActiveRulesByNozzle();
+        BigDecimal selectedNozzle = nozzleLayerHeightPolicyService.resolveNozzle(
+                nozzleDiameter != null ? BigDecimal.valueOf(nozzleDiameter) : null
+        );
+
+        List<OptionsResponse.LayerHeightOptionDTO> layers = toLayerDtos(rulesByNozzle.getOrDefault(selectedNozzle, List.of()));
+        if (layers.isEmpty()) {
+            layers = rulesByNozzle.values().stream().findFirst().map(this::toLayerDtos).orElse(List.of());
+        }
+
+        List<OptionsResponse.NozzleLayerHeightOptionsDTO> layerHeightsByNozzle = rulesByNozzle.entrySet().stream()
+                .map(entry -> new OptionsResponse.NozzleLayerHeightOptionsDTO(
+                        entry.getKey().doubleValue(),
+                        toLayerDtos(entry.getValue())
+                ))
+                .toList();
+
+        return ResponseEntity.ok(new OptionsResponse(
+                materialOptions,
+                qualities,
+                patterns,
+                layers,
+                nozzles,
+                layerHeightsByNozzle
+        ));
     }
 
     private Set<Long> resolveCompatibleMaterialTypeIds(Long printerMachineId, Double nozzleDiameter) {
@@ -152,9 +167,9 @@ public class OptionsController {
             return Set.of();
         }
 
-        BigDecimal nozzle = nozzleDiameter != null
-                ? BigDecimal.valueOf(nozzleDiameter)
-                : BigDecimal.valueOf(0.40);
+        BigDecimal nozzle = nozzleLayerHeightPolicyService.resolveNozzle(
+                nozzleDiameter != null ? BigDecimal.valueOf(nozzleDiameter) : null
+        );
 
         PrinterMachineProfile machineProfile = orcaProfileResolver
                 .resolveMachineProfile(machine, nozzle)
@@ -172,6 +187,16 @@ public class OptionsController {
                 .collect(Collectors.toSet());
     }
 
+    private List<OptionsResponse.LayerHeightOptionDTO> toLayerDtos(List<BigDecimal> layers) {
+        return layers.stream()
+                .sorted(Comparator.naturalOrder())
+                .map(layer -> new OptionsResponse.LayerHeightOptionDTO(
+                        layer.doubleValue(),
+                        String.format("%.2f mm", layer)
+                ))
+                .toList();
+    }
+
     private String resolveHexColor(FilamentVariant variant) {
         if (variant.getColorHex() != null && !variant.getColorHex().isBlank()) {
             return variant.getColorHex();
diff --git a/backend/src/main/java/com/printcalculator/controller/OrderController.java b/backend/src/main/java/com/printcalculator/controller/OrderController.java
index c8a2b5c..eb11a76 100644
--- a/backend/src/main/java/com/printcalculator/controller/OrderController.java
+++ b/backend/src/main/java/com/printcalculator/controller/OrderController.java
@@ -3,12 +3,12 @@ package com.printcalculator.controller;
 import com.printcalculator.dto.*;
 import com.printcalculator.entity.*;
 import com.printcalculator.repository.*;
-import com.printcalculator.service.InvoicePdfRenderingService;
+import com.printcalculator.service.payment.InvoicePdfRenderingService;
 import com.printcalculator.service.OrderService;
-import com.printcalculator.service.PaymentService;
-import com.printcalculator.service.QrBillService;
-import com.printcalculator.service.StorageService;
-import com.printcalculator.service.TwintPaymentService;
+import com.printcalculator.service.payment.PaymentService;
+import com.printcalculator.service.payment.QrBillService;
+import com.printcalculator.service.storage.StorageService;
+import com.printcalculator.service.payment.TwintPaymentService;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.util.StringUtils;
diff --git a/backend/src/main/java/com/printcalculator/controller/QuoteController.java b/backend/src/main/java/com/printcalculator/controller/QuoteController.java
index 45369c1..8675415 100644
--- a/backend/src/main/java/com/printcalculator/controller/QuoteController.java
+++ b/backend/src/main/java/com/printcalculator/controller/QuoteController.java
@@ -4,17 +4,23 @@ import com.printcalculator.entity.PrinterMachine;
 import com.printcalculator.model.PrintStats;
 import com.printcalculator.model.QuoteResult;
 import com.printcalculator.repository.PrinterMachineRepository;
+import com.printcalculator.service.NozzleLayerHeightPolicyService;
 import com.printcalculator.service.QuoteCalculator;
 import com.printcalculator.service.SlicerService;
+import com.printcalculator.service.storage.ClamAVService;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 import org.springframework.web.multipart.MultipartFile;
+import org.springframework.web.server.ResponseStatusException;
 
-import java.util.Map;
-import java.util.HashMap;
 import java.io.IOException;
+import java.math.BigDecimal;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.springframework.http.HttpStatus.BAD_REQUEST;
 
 @RestController
 public class QuoteController {
@@ -22,17 +28,23 @@ public class QuoteController {
     private final SlicerService slicerService;
     private final QuoteCalculator quoteCalculator;
     private final PrinterMachineRepository machineRepo;
-    private final com.printcalculator.service.ClamAVService clamAVService;
+    private final ClamAVService clamAVService;
+    private final NozzleLayerHeightPolicyService nozzleLayerHeightPolicyService;
 
     // Defaults (using aliases defined in ProfileManager)
     private static final String DEFAULT_FILAMENT = "pla_basic";
     private static final String DEFAULT_PROCESS = "standard";
 
-    public QuoteController(SlicerService slicerService, QuoteCalculator quoteCalculator, PrinterMachineRepository machineRepo, com.printcalculator.service.ClamAVService clamAVService) {
+    public QuoteController(SlicerService slicerService,
+                           QuoteCalculator quoteCalculator,
+                           PrinterMachineRepository machineRepo,
+                           ClamAVService clamAVService,
+                           NozzleLayerHeightPolicyService nozzleLayerHeightPolicyService) {
         this.slicerService = slicerService;
         this.quoteCalculator = quoteCalculator;
         this.machineRepo = machineRepo;
         this.clamAVService = clamAVService;
+        this.nozzleLayerHeightPolicyService = nozzleLayerHeightPolicyService;
     }
 
     @PostMapping("/api/quote")
@@ -69,15 +81,27 @@ public class QuoteController {
         if (infillPattern != null && !infillPattern.isEmpty()) {
             processOverrides.put("sparse_infill_pattern", infillPattern);
         }
+        BigDecimal normalizedNozzle = nozzleLayerHeightPolicyService.resolveNozzle(
+                nozzleDiameter != null ? BigDecimal.valueOf(nozzleDiameter) : null
+        );
         if (layerHeight != null) {
-            processOverrides.put("layer_height", String.valueOf(layerHeight));
+            BigDecimal normalizedLayer = nozzleLayerHeightPolicyService.normalizeLayer(BigDecimal.valueOf(layerHeight));
+            if (!nozzleLayerHeightPolicyService.isAllowed(normalizedNozzle, normalizedLayer)) {
+                throw new ResponseStatusException(
+                        BAD_REQUEST,
+                        "Layer height " + normalizedLayer.stripTrailingZeros().toPlainString()
+                                + " is not allowed for nozzle " + normalizedNozzle.stripTrailingZeros().toPlainString()
+                                + ". Allowed: " + nozzleLayerHeightPolicyService.allowedLayersLabel(normalizedNozzle)
+                );
+            }
+            processOverrides.put("layer_height", normalizedLayer.stripTrailingZeros().toPlainString());
         }
         if (supportEnabled != null) {
             processOverrides.put("enable_support", supportEnabled ? "1" : "0");
         }
 
         if (nozzleDiameter != null) {
-            machineOverrides.put("nozzle_diameter", String.valueOf(nozzleDiameter));
+            machineOverrides.put("nozzle_diameter", normalizedNozzle.stripTrailingZeros().toPlainString());
             // Also need to ensure the printer profile is compatible or just override?
             // Usually nozzle diameter changes require a different printer profile or deep overrides.
             // For now, we trust the override key works on the base profile.
diff --git a/backend/src/main/java/com/printcalculator/controller/QuoteSessionController.java b/backend/src/main/java/com/printcalculator/controller/QuoteSessionController.java
index 70689ac..803a045 100644
--- a/backend/src/main/java/com/printcalculator/controller/QuoteSessionController.java
+++ b/backend/src/main/java/com/printcalculator/controller/QuoteSessionController.java
@@ -14,9 +14,11 @@ import com.printcalculator.repository.PrinterMachineRepository;
 import com.printcalculator.repository.QuoteLineItemRepository;
 import com.printcalculator.repository.QuoteSessionRepository;
 import com.printcalculator.service.OrcaProfileResolver;
+import com.printcalculator.service.NozzleLayerHeightPolicyService;
 import com.printcalculator.service.QuoteCalculator;
 import com.printcalculator.service.QuoteSessionTotalsService;
 import com.printcalculator.service.SlicerService;
+import com.printcalculator.service.storage.ClamAVService;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.transaction.annotation.Transactional;
@@ -61,8 +63,9 @@ public class QuoteSessionController {
     private final FilamentMaterialTypeRepository materialRepo;
     private final FilamentVariantRepository variantRepo;
     private final OrcaProfileResolver orcaProfileResolver;
+    private final NozzleLayerHeightPolicyService nozzleLayerHeightPolicyService;
     private final com.printcalculator.repository.PricingPolicyRepository pricingRepo;
-    private final com.printcalculator.service.ClamAVService clamAVService;
+    private final ClamAVService clamAVService;
     private final QuoteSessionTotalsService quoteSessionTotalsService;
 
     public QuoteSessionController(QuoteSessionRepository sessionRepo,
@@ -73,8 +76,9 @@ public class QuoteSessionController {
                                   FilamentMaterialTypeRepository materialRepo,
                                   FilamentVariantRepository variantRepo,
                                   OrcaProfileResolver orcaProfileResolver,
+                                  NozzleLayerHeightPolicyService nozzleLayerHeightPolicyService,
                                   com.printcalculator.repository.PricingPolicyRepository pricingRepo,
-                                  com.printcalculator.service.ClamAVService clamAVService,
+                                  ClamAVService clamAVService,
                                   QuoteSessionTotalsService quoteSessionTotalsService) {
         this.sessionRepo = sessionRepo;
         this.lineItemRepo = lineItemRepo;
@@ -84,6 +88,7 @@ public class QuoteSessionController {
         this.materialRepo = materialRepo;
         this.variantRepo = variantRepo;
         this.orcaProfileResolver = orcaProfileResolver;
+        this.nozzleLayerHeightPolicyService = nozzleLayerHeightPolicyService;
         this.pricingRepo = pricingRepo;
         this.clamAVService = clamAVService;
         this.quoteSessionTotalsService = quoteSessionTotalsService;
@@ -167,7 +172,23 @@ public class QuoteSessionController {
                 applyPrintSettings(settings);
             }
 
-            BigDecimal nozzleDiameter = BigDecimal.valueOf(settings.getNozzleDiameter() != null ? settings.getNozzleDiameter() : 0.4);
+            BigDecimal nozzleDiameter = nozzleLayerHeightPolicyService.resolveNozzle(
+                    settings.getNozzleDiameter() != null ? BigDecimal.valueOf(settings.getNozzleDiameter()) : null
+            );
+            BigDecimal layerHeight = nozzleLayerHeightPolicyService.resolveLayer(
+                    settings.getLayerHeight() != null ? BigDecimal.valueOf(settings.getLayerHeight()) : null,
+                    nozzleDiameter
+            );
+            if (!nozzleLayerHeightPolicyService.isAllowed(nozzleDiameter, layerHeight)) {
+                throw new ResponseStatusException(
+                        BAD_REQUEST,
+                        "Layer height " + layerHeight.stripTrailingZeros().toPlainString()
+                                + " is not allowed for nozzle " + nozzleDiameter.stripTrailingZeros().toPlainString()
+                                + ". Allowed: " + nozzleLayerHeightPolicyService.allowedLayersLabel(nozzleDiameter)
+                );
+            }
+            settings.setNozzleDiameter(nozzleDiameter.doubleValue());
+            settings.setLayerHeight(layerHeight.doubleValue());
 
             // Pick machine (selected machine if provided, otherwise first active)
             PrinterMachine machine = resolvePrinterMachine(settings.getPrinterMachineId());
@@ -190,7 +211,7 @@ public class QuoteSessionController {
             if (!cadSession) {
                 session.setMaterialCode(selectedVariant.getFilamentMaterialType().getMaterialCode());
                 session.setNozzleDiameterMm(nozzleDiameter);
-                session.setLayerHeightMm(BigDecimal.valueOf(settings.getLayerHeight() != null ? settings.getLayerHeight() : 0.2));
+                session.setLayerHeightMm(layerHeight);
                 session.setInfillPattern(settings.getInfillPattern());
                 session.setInfillPercent(settings.getInfillDensity() != null ? settings.getInfillDensity().intValue() : 20);
                 session.setSupportsEnabled(settings.getSupportsEnabled() != null ? settings.getSupportsEnabled() : false);
@@ -209,7 +230,7 @@ public class QuoteSessionController {
             
             // Build overrides map from settings
             Map<String, String> processOverrides = new HashMap<>();
-            if (settings.getLayerHeight() != null) processOverrides.put("layer_height", String.valueOf(settings.getLayerHeight()));
+            processOverrides.put("layer_height", layerHeight.stripTrailingZeros().toPlainString());
             if (settings.getInfillDensity() != null) processOverrides.put("sparse_infill_density", settings.getInfillDensity() + "%");
             if (settings.getInfillPattern() != null) processOverrides.put("sparse_infill_pattern", settings.getInfillPattern());
 
@@ -289,6 +310,10 @@ public class QuoteSessionController {
     }
 
     private void applyPrintSettings(com.printcalculator.dto.PrintSettingsDto settings) {
+        if (settings.getNozzleDiameter() == null) {
+            settings.setNozzleDiameter(0.40);
+        }
+
         if ("BASIC".equalsIgnoreCase(settings.getComplexityMode())) {
             // Set defaults based on Quality
             String quality = settings.getQuality() != null ? settings.getQuality().toLowerCase() : "standard";
@@ -313,7 +338,6 @@ public class QuoteSessionController {
             }
         } else {
             // ADVANCED Mode: Use values from Frontend, set defaults if missing
-            if (settings.getLayerHeight() == null) settings.setLayerHeight(0.20);
             if (settings.getInfillDensity() == null) settings.setInfillDensity(20.0);
             if (settings.getInfillPattern() == null) settings.setInfillPattern("grid");
         }
diff --git a/backend/src/main/java/com/printcalculator/controller/admin/AdminOrderController.java b/backend/src/main/java/com/printcalculator/controller/admin/AdminOrderController.java
index 764940d..c41e8c1 100644
--- a/backend/src/main/java/com/printcalculator/controller/admin/AdminOrderController.java
+++ b/backend/src/main/java/com/printcalculator/controller/admin/AdminOrderController.java
@@ -12,10 +12,10 @@ import com.printcalculator.event.OrderShippedEvent;
 import com.printcalculator.repository.OrderItemRepository;
 import com.printcalculator.repository.OrderRepository;
 import com.printcalculator.repository.PaymentRepository;
-import com.printcalculator.service.InvoicePdfRenderingService;
-import com.printcalculator.service.PaymentService;
-import com.printcalculator.service.QrBillService;
-import com.printcalculator.service.StorageService;
+import com.printcalculator.service.payment.InvoicePdfRenderingService;
+import com.printcalculator.service.payment.PaymentService;
+import com.printcalculator.service.payment.QrBillService;
+import com.printcalculator.service.storage.StorageService;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.core.io.Resource;
 import org.springframework.http.ContentDisposition;
@@ -34,7 +34,6 @@ import org.springframework.web.server.ResponseStatusException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.InvalidPathException;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
diff --git a/backend/src/main/java/com/printcalculator/dto/OptionsResponse.java b/backend/src/main/java/com/printcalculator/dto/OptionsResponse.java
index 54d7e87..9b85460 100644
--- a/backend/src/main/java/com/printcalculator/dto/OptionsResponse.java
+++ b/backend/src/main/java/com/printcalculator/dto/OptionsResponse.java
@@ -7,7 +7,8 @@ public record OptionsResponse(
     List<QualityOption> qualities,
     List<InfillPatternOption> infillPatterns,
     List<LayerHeightOptionDTO> layerHeights,
-    List<NozzleOptionDTO> nozzleDiameters
+    List<NozzleOptionDTO> nozzleDiameters,
+    List<NozzleLayerHeightOptionsDTO> layerHeightsByNozzle
 ) {
     public record MaterialOption(String code, String label, List<VariantOption> variants) {}
     public record VariantOption(
@@ -24,4 +25,5 @@ public record OptionsResponse(
     public record InfillPatternOption(String id, String label) {}
     public record LayerHeightOptionDTO(double value, String label) {}
     public record NozzleOptionDTO(double value, String label) {}
+    public record NozzleLayerHeightOptionsDTO(double nozzleDiameter, List<LayerHeightOptionDTO> layerHeights) {}
 }
diff --git a/backend/src/main/java/com/printcalculator/entity/NozzleLayerHeightOption.java b/backend/src/main/java/com/printcalculator/entity/NozzleLayerHeightOption.java
new file mode 100644
index 0000000..bf2de56
--- /dev/null
+++ b/backend/src/main/java/com/printcalculator/entity/NozzleLayerHeightOption.java
@@ -0,0 +1,63 @@
+package com.printcalculator.entity;
+
+import jakarta.persistence.*;
+import org.hibernate.annotations.ColumnDefault;
+
+import java.math.BigDecimal;
+
+@Entity
+@Table(
+        name = "nozzle_layer_height_option",
+        uniqueConstraints = @UniqueConstraint(
+                name = "ux_nozzle_layer_height_option_nozzle_layer",
+                columnNames = {"nozzle_diameter_mm", "layer_height_mm"}
+        )
+)
+public class NozzleLayerHeightOption {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "nozzle_layer_height_option_id", nullable = false)
+    private Long id;
+
+    @Column(name = "nozzle_diameter_mm", nullable = false, precision = 4, scale = 2)
+    private BigDecimal nozzleDiameterMm;
+
+    @Column(name = "layer_height_mm", nullable = false, precision = 5, scale = 3)
+    private BigDecimal layerHeightMm;
+
+    @ColumnDefault("true")
+    @Column(name = "is_active", nullable = false)
+    private Boolean isActive;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public BigDecimal getNozzleDiameterMm() {
+        return nozzleDiameterMm;
+    }
+
+    public void setNozzleDiameterMm(BigDecimal nozzleDiameterMm) {
+        this.nozzleDiameterMm = nozzleDiameterMm;
+    }
+
+    public BigDecimal getLayerHeightMm() {
+        return layerHeightMm;
+    }
+
+    public void setLayerHeightMm(BigDecimal layerHeightMm) {
+        this.layerHeightMm = layerHeightMm;
+    }
+
+    public Boolean getIsActive() {
+        return isActive;
+    }
+
+    public void setIsActive(Boolean isActive) {
+        this.isActive = isActive;
+    }
+}
diff --git a/backend/src/main/java/com/printcalculator/event/listener/OrderEmailListener.java b/backend/src/main/java/com/printcalculator/event/listener/OrderEmailListener.java
index a1cfaa2..27b349c 100644
--- a/backend/src/main/java/com/printcalculator/event/listener/OrderEmailListener.java
+++ b/backend/src/main/java/com/printcalculator/event/listener/OrderEmailListener.java
@@ -8,9 +8,9 @@ import com.printcalculator.event.OrderShippedEvent;
 import com.printcalculator.event.PaymentConfirmedEvent;
 import com.printcalculator.event.PaymentReportedEvent;
 import com.printcalculator.repository.OrderItemRepository;
-import com.printcalculator.service.InvoicePdfRenderingService;
-import com.printcalculator.service.QrBillService;
-import com.printcalculator.service.StorageService;
+import com.printcalculator.service.payment.InvoicePdfRenderingService;
+import com.printcalculator.service.payment.QrBillService;
+import com.printcalculator.service.storage.StorageService;
 import com.printcalculator.service.email.EmailNotificationService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
diff --git a/backend/src/main/java/com/printcalculator/repository/NozzleLayerHeightOptionRepository.java b/backend/src/main/java/com/printcalculator/repository/NozzleLayerHeightOptionRepository.java
new file mode 100644
index 0000000..38973fb
--- /dev/null
+++ b/backend/src/main/java/com/printcalculator/repository/NozzleLayerHeightOptionRepository.java
@@ -0,0 +1,10 @@
+package com.printcalculator.repository;
+
+import com.printcalculator.entity.NozzleLayerHeightOption;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.List;
+
+public interface NozzleLayerHeightOptionRepository extends JpaRepository<NozzleLayerHeightOption, Long> {
+    List<NozzleLayerHeightOption> findByIsActiveTrueOrderByNozzleDiameterMmAscLayerHeightMmAsc();
+}
diff --git a/backend/src/main/java/com/printcalculator/service/NozzleLayerHeightPolicyService.java b/backend/src/main/java/com/printcalculator/service/NozzleLayerHeightPolicyService.java
new file mode 100644
index 0000000..4898209
--- /dev/null
+++ b/backend/src/main/java/com/printcalculator/service/NozzleLayerHeightPolicyService.java
@@ -0,0 +1,143 @@
+package com.printcalculator.service;
+
+import com.printcalculator.entity.NozzleLayerHeightOption;
+import com.printcalculator.repository.NozzleLayerHeightOptionRepository;
+import org.springframework.stereotype.Service;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+@Service
+public class NozzleLayerHeightPolicyService {
+    private static final BigDecimal DEFAULT_NOZZLE = BigDecimal.valueOf(0.40).setScale(2, RoundingMode.HALF_UP);
+    private static final BigDecimal DEFAULT_LAYER = BigDecimal.valueOf(0.20).setScale(3, RoundingMode.HALF_UP);
+
+    private final NozzleLayerHeightOptionRepository ruleRepo;
+
+    public NozzleLayerHeightPolicyService(NozzleLayerHeightOptionRepository ruleRepo) {
+        this.ruleRepo = ruleRepo;
+    }
+
+    public Map<BigDecimal, List<BigDecimal>> getActiveRulesByNozzle() {
+        List<NozzleLayerHeightOption> rules = ruleRepo.findByIsActiveTrueOrderByNozzleDiameterMmAscLayerHeightMmAsc();
+        if (rules.isEmpty()) {
+            return fallbackRules();
+        }
+
+        Map<BigDecimal, List<BigDecimal>> byNozzle = new LinkedHashMap<>();
+        for (NozzleLayerHeightOption rule : rules) {
+            BigDecimal nozzle = normalizeNozzle(rule.getNozzleDiameterMm());
+            BigDecimal layer = normalizeLayer(rule.getLayerHeightMm());
+            if (nozzle == null || layer == null) {
+                continue;
+            }
+            byNozzle.computeIfAbsent(nozzle, ignored -> new ArrayList<>()).add(layer);
+        }
+
+        byNozzle.values().forEach(this::sortAndDeduplicate);
+        return byNozzle;
+    }
+
+    public BigDecimal normalizeNozzle(BigDecimal value) {
+        if (value == null) {
+            return null;
+        }
+        return value.setScale(2, RoundingMode.HALF_UP);
+    }
+
+    public BigDecimal normalizeLayer(BigDecimal value) {
+        if (value == null) {
+            return null;
+        }
+        return value.setScale(3, RoundingMode.HALF_UP);
+    }
+
+    public BigDecimal resolveNozzle(BigDecimal requestedNozzle) {
+        return normalizeNozzle(requestedNozzle != null ? requestedNozzle : DEFAULT_NOZZLE);
+    }
+
+    public BigDecimal resolveLayer(BigDecimal requestedLayer, BigDecimal nozzleDiameter) {
+        if (requestedLayer != null) {
+            return normalizeLayer(requestedLayer);
+        }
+        return defaultLayerForNozzle(nozzleDiameter);
+    }
+
+    public List<BigDecimal> allowedLayersForNozzle(BigDecimal nozzleDiameter) {
+        BigDecimal nozzle = resolveNozzle(nozzleDiameter);
+        List<BigDecimal> allowed = getActiveRulesByNozzle().get(nozzle);
+        return allowed != null ? allowed : List.of();
+    }
+
+    public boolean isAllowed(BigDecimal nozzleDiameter, BigDecimal layerHeight) {
+        BigDecimal layer = normalizeLayer(layerHeight);
+        if (layer == null) {
+            return false;
+        }
+        return allowedLayersForNozzle(nozzleDiameter)
+                .stream()
+                .anyMatch(allowed -> allowed.compareTo(layer) == 0);
+    }
+
+    public BigDecimal defaultLayerForNozzle(BigDecimal nozzleDiameter) {
+        List<BigDecimal> allowed = allowedLayersForNozzle(nozzleDiameter);
+        if (allowed.isEmpty()) {
+            return DEFAULT_LAYER;
+        }
+
+        BigDecimal preferred = normalizeLayer(DEFAULT_LAYER);
+        for (BigDecimal candidate : allowed) {
+            if (candidate.compareTo(preferred) == 0) {
+                return candidate;
+            }
+        }
+        return allowed.get(0);
+    }
+
+    public String allowedLayersLabel(BigDecimal nozzleDiameter) {
+        List<BigDecimal> allowed = allowedLayersForNozzle(nozzleDiameter);
+        if (allowed.isEmpty()) {
+            return "none";
+        }
+        return allowed.stream()
+                .map(value -> String.format(Locale.ROOT, "%.2f", value))
+                .reduce((a, b) -> a + ", " + b)
+                .orElse("none");
+    }
+
+    private void sortAndDeduplicate(List<BigDecimal> values) {
+        values.sort(Comparator.naturalOrder());
+        for (int i = values.size() - 1; i > 0; i--) {
+            if (values.get(i).compareTo(values.get(i - 1)) == 0) {
+                values.remove(i);
+            }
+        }
+    }
+
+    private Map<BigDecimal, List<BigDecimal>> fallbackRules() {
+        Map<BigDecimal, List<BigDecimal>> fallback = new LinkedHashMap<>();
+        fallback.put(scaleNozzle(0.20), scaleLayers(0.04, 0.06, 0.08, 0.10, 0.12));
+        fallback.put(scaleNozzle(0.40), scaleLayers(0.08, 0.12, 0.16, 0.20, 0.24, 0.28));
+        fallback.put(scaleNozzle(0.60), scaleLayers(0.16, 0.20, 0.24, 0.30, 0.36));
+        fallback.put(scaleNozzle(0.80), scaleLayers(0.20, 0.28, 0.36, 0.40, 0.48, 0.56));
+        return fallback;
+    }
+
+    private BigDecimal scaleNozzle(double value) {
+        return BigDecimal.valueOf(value).setScale(2, RoundingMode.HALF_UP);
+    }
+
+    private List<BigDecimal> scaleLayers(double... values) {
+        List<BigDecimal> scaled = new ArrayList<>();
+        for (double value : values) {
+            scaled.add(BigDecimal.valueOf(value).setScale(3, RoundingMode.HALF_UP));
+        }
+        return scaled;
+    }
+}
diff --git a/backend/src/main/java/com/printcalculator/service/OrderService.java b/backend/src/main/java/com/printcalculator/service/OrderService.java
index 3a1f606..f42b17c 100644
--- a/backend/src/main/java/com/printcalculator/service/OrderService.java
+++ b/backend/src/main/java/com/printcalculator/service/OrderService.java
@@ -8,6 +8,10 @@ import com.printcalculator.repository.OrderRepository;
 import com.printcalculator.repository.QuoteLineItemRepository;
 import com.printcalculator.repository.QuoteSessionRepository;
 import com.printcalculator.event.OrderCreatedEvent;
+import com.printcalculator.service.payment.InvoicePdfRenderingService;
+import com.printcalculator.service.payment.PaymentService;
+import com.printcalculator.service.payment.QrBillService;
+import com.printcalculator.service.storage.StorageService;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
diff --git a/backend/src/main/java/com/printcalculator/service/InvoicePdfRenderingService.java b/backend/src/main/java/com/printcalculator/service/payment/InvoicePdfRenderingService.java
similarity index 99%
rename from backend/src/main/java/com/printcalculator/service/InvoicePdfRenderingService.java
rename to backend/src/main/java/com/printcalculator/service/payment/InvoicePdfRenderingService.java
index 97840bf..96ec578 100644
--- a/backend/src/main/java/com/printcalculator/service/InvoicePdfRenderingService.java
+++ b/backend/src/main/java/com/printcalculator/service/payment/InvoicePdfRenderingService.java
@@ -1,4 +1,4 @@
-package com.printcalculator.service;
+package com.printcalculator.service.payment;
 
 import com.openhtmltopdf.pdfboxout.PdfRendererBuilder;
 import com.openhtmltopdf.svgsupport.BatikSVGDrawer;
diff --git a/backend/src/main/java/com/printcalculator/service/PaymentService.java b/backend/src/main/java/com/printcalculator/service/payment/PaymentService.java
similarity index 96%
rename from backend/src/main/java/com/printcalculator/service/PaymentService.java
rename to backend/src/main/java/com/printcalculator/service/payment/PaymentService.java
index 23b907c..4be56c3 100644
--- a/backend/src/main/java/com/printcalculator/service/PaymentService.java
+++ b/backend/src/main/java/com/printcalculator/service/payment/PaymentService.java
@@ -1,4 +1,4 @@
-package com.printcalculator.service;
+package com.printcalculator.service.payment;
 
 import com.printcalculator.entity.Order;
 import com.printcalculator.entity.Payment;
@@ -65,7 +65,7 @@ public class PaymentService {
         payment.setReportedAt(OffsetDateTime.now());
         
         // We intentionally do not update the payment method here based on user input,
-        // because the user cannot reliably determine the actual method without an integration.
+        // because the system cannot reliably determine the actual method without an integration.
         // It will be updated by the backoffice admin manually.
 
         payment = paymentRepo.save(payment);
diff --git a/backend/src/main/java/com/printcalculator/service/QrBillService.java b/backend/src/main/java/com/printcalculator/service/payment/QrBillService.java
similarity index 94%
rename from backend/src/main/java/com/printcalculator/service/QrBillService.java
rename to backend/src/main/java/com/printcalculator/service/payment/QrBillService.java
index 71eb47c..a6dbed7 100644
--- a/backend/src/main/java/com/printcalculator/service/QrBillService.java
+++ b/backend/src/main/java/com/printcalculator/service/payment/QrBillService.java
@@ -1,13 +1,10 @@
-package com.printcalculator.service;
+package com.printcalculator.service.payment;
 
 import com.printcalculator.entity.Order;
 import net.codecrete.qrbill.generator.Bill;
-import net.codecrete.qrbill.generator.GraphicsFormat;
 import net.codecrete.qrbill.generator.QRBill;
 import org.springframework.stereotype.Service;
 
-import java.math.BigDecimal;
-
 @Service
 public class QrBillService {
 
diff --git a/backend/src/main/java/com/printcalculator/service/TwintPaymentService.java b/backend/src/main/java/com/printcalculator/service/payment/TwintPaymentService.java
similarity index 98%
rename from backend/src/main/java/com/printcalculator/service/TwintPaymentService.java
rename to backend/src/main/java/com/printcalculator/service/payment/TwintPaymentService.java
index 6ed915b..a7be8eb 100644
--- a/backend/src/main/java/com/printcalculator/service/TwintPaymentService.java
+++ b/backend/src/main/java/com/printcalculator/service/payment/TwintPaymentService.java
@@ -1,4 +1,4 @@
-package com.printcalculator.service;
+package com.printcalculator.service.payment;
 
 import io.nayuki.qrcodegen.QrCode;
 import org.springframework.beans.factory.annotation.Value;
diff --git a/backend/src/main/java/com/printcalculator/service/ClamAVService.java b/backend/src/main/java/com/printcalculator/service/storage/ClamAVService.java
similarity index 98%
rename from backend/src/main/java/com/printcalculator/service/ClamAVService.java
rename to backend/src/main/java/com/printcalculator/service/storage/ClamAVService.java
index dc6532a..ceed6e7 100644
--- a/backend/src/main/java/com/printcalculator/service/ClamAVService.java
+++ b/backend/src/main/java/com/printcalculator/service/storage/ClamAVService.java
@@ -1,4 +1,4 @@
-package com.printcalculator.service;
+package com.printcalculator.service.storage;
 
 import com.printcalculator.exception.VirusDetectedException;
 import org.slf4j.Logger;
diff --git a/backend/src/main/java/com/printcalculator/service/FileSystemStorageService.java b/backend/src/main/java/com/printcalculator/service/storage/FileSystemStorageService.java
similarity index 98%
rename from backend/src/main/java/com/printcalculator/service/FileSystemStorageService.java
rename to backend/src/main/java/com/printcalculator/service/storage/FileSystemStorageService.java
index 38e1e25..d4bf9d3 100644
--- a/backend/src/main/java/com/printcalculator/service/FileSystemStorageService.java
+++ b/backend/src/main/java/com/printcalculator/service/storage/FileSystemStorageService.java
@@ -1,4 +1,4 @@
-package com.printcalculator.service;
+package com.printcalculator.service.storage;
 
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.core.io.Resource;
@@ -7,7 +7,6 @@ import org.springframework.stereotype.Service;
 import org.springframework.web.multipart.MultipartFile;
 import com.printcalculator.exception.StorageException;
 
-import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
diff --git a/backend/src/main/java/com/printcalculator/service/StorageService.java b/backend/src/main/java/com/printcalculator/service/storage/StorageService.java
similarity index 91%
rename from backend/src/main/java/com/printcalculator/service/StorageService.java
rename to backend/src/main/java/com/printcalculator/service/storage/StorageService.java
index 5fe2321..89773a8 100644
--- a/backend/src/main/java/com/printcalculator/service/StorageService.java
+++ b/backend/src/main/java/com/printcalculator/service/storage/StorageService.java
@@ -1,4 +1,4 @@
-package com.printcalculator.service;
+package com.printcalculator.service.storage;
 
 import org.springframework.core.io.Resource;
 import org.springframework.web.multipart.MultipartFile;
diff --git a/backend/src/test/java/com/printcalculator/controller/OrderControllerPrivacyTest.java b/backend/src/test/java/com/printcalculator/controller/OrderControllerPrivacyTest.java
index b3d6665..5849c12 100644
--- a/backend/src/test/java/com/printcalculator/controller/OrderControllerPrivacyTest.java
+++ b/backend/src/test/java/com/printcalculator/controller/OrderControllerPrivacyTest.java
@@ -8,12 +8,12 @@ import com.printcalculator.repository.OrderRepository;
 import com.printcalculator.repository.PaymentRepository;
 import com.printcalculator.repository.QuoteLineItemRepository;
 import com.printcalculator.repository.QuoteSessionRepository;
-import com.printcalculator.service.InvoicePdfRenderingService;
+import com.printcalculator.service.payment.InvoicePdfRenderingService;
 import com.printcalculator.service.OrderService;
-import com.printcalculator.service.PaymentService;
-import com.printcalculator.service.QrBillService;
-import com.printcalculator.service.StorageService;
-import com.printcalculator.service.TwintPaymentService;
+import com.printcalculator.service.payment.PaymentService;
+import com.printcalculator.service.payment.QrBillService;
+import com.printcalculator.service.storage.StorageService;
+import com.printcalculator.service.payment.TwintPaymentService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
diff --git a/backend/src/test/java/com/printcalculator/controller/admin/AdminOrderControllerStatusValidationTest.java b/backend/src/test/java/com/printcalculator/controller/admin/AdminOrderControllerStatusValidationTest.java
index 88701dd..804da16 100644
--- a/backend/src/test/java/com/printcalculator/controller/admin/AdminOrderControllerStatusValidationTest.java
+++ b/backend/src/test/java/com/printcalculator/controller/admin/AdminOrderControllerStatusValidationTest.java
@@ -6,10 +6,10 @@ import com.printcalculator.entity.Order;
 import com.printcalculator.repository.OrderItemRepository;
 import com.printcalculator.repository.OrderRepository;
 import com.printcalculator.repository.PaymentRepository;
-import com.printcalculator.service.InvoicePdfRenderingService;
-import com.printcalculator.service.PaymentService;
-import com.printcalculator.service.QrBillService;
-import com.printcalculator.service.StorageService;
+import com.printcalculator.service.payment.InvoicePdfRenderingService;
+import com.printcalculator.service.payment.PaymentService;
+import com.printcalculator.service.payment.QrBillService;
+import com.printcalculator.service.storage.StorageService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
diff --git a/backend/src/test/java/com/printcalculator/event/listener/OrderEmailListenerTest.java b/backend/src/test/java/com/printcalculator/event/listener/OrderEmailListenerTest.java
index b0f62c4..6c06bc4 100644
--- a/backend/src/test/java/com/printcalculator/event/listener/OrderEmailListenerTest.java
+++ b/backend/src/test/java/com/printcalculator/event/listener/OrderEmailListenerTest.java
@@ -4,9 +4,9 @@ import com.printcalculator.entity.Customer;
 import com.printcalculator.entity.Order;
 import com.printcalculator.event.OrderCreatedEvent;
 import com.printcalculator.repository.OrderItemRepository;
-import com.printcalculator.service.InvoicePdfRenderingService;
-import com.printcalculator.service.QrBillService;
-import com.printcalculator.service.StorageService;
+import com.printcalculator.service.payment.InvoicePdfRenderingService;
+import com.printcalculator.service.payment.QrBillService;
+import com.printcalculator.service.storage.StorageService;
 import com.printcalculator.service.email.EmailNotificationService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
diff --git a/frontend/public/robots.txt b/frontend/public/robots.txt
new file mode 100644
index 0000000..6bd7b9c
--- /dev/null
+++ b/frontend/public/robots.txt
@@ -0,0 +1,21 @@
+User-agent: *
+Allow: /
+
+Disallow: /admin
+Disallow: /admin/
+Disallow: /*/admin
+Disallow: /*/admin/
+Disallow: /order/
+Disallow: /*/order/
+Disallow: /co/
+Disallow: /*/co/
+Disallow: /checkout
+Disallow: /checkout/
+Disallow: /*/checkout
+Disallow: /*/checkout/
+Disallow: /shop
+Disallow: /shop/
+Disallow: /*/shop
+Disallow: /*/shop/
+
+Sitemap: https://3d-fab.ch/sitemap.xml
diff --git a/frontend/public/sitemap.xml b/frontend/public/sitemap.xml
new file mode 100644
index 0000000..a1195d2
--- /dev/null
+++ b/frontend/public/sitemap.xml
@@ -0,0 +1,144 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<urlset
+  xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
+  xmlns:xhtml="http://www.w3.org/1999/xhtml"
+>
+  <url>
+    <loc>https://3d-fab.ch/it</loc>
+    <xhtml:link rel="alternate" hreflang="it" href="https://3d-fab.ch/it" />
+    <xhtml:link rel="alternate" hreflang="en" href="https://3d-fab.ch/en" />
+    <xhtml:link rel="alternate" hreflang="de" href="https://3d-fab.ch/de" />
+    <xhtml:link rel="alternate" hreflang="fr" href="https://3d-fab.ch/fr" />
+    <xhtml:link rel="alternate" hreflang="x-default" href="https://3d-fab.ch/it" />
+    <changefreq>weekly</changefreq>
+    <priority>1.0</priority>
+  </url>
+  <url>
+    <loc>https://3d-fab.ch/it/calculator/basic</loc>
+    <xhtml:link
+      rel="alternate"
+      hreflang="it"
+      href="https://3d-fab.ch/it/calculator/basic"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="en"
+      href="https://3d-fab.ch/en/calculator/basic"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="de"
+      href="https://3d-fab.ch/de/calculator/basic"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="fr"
+      href="https://3d-fab.ch/fr/calculator/basic"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="x-default"
+      href="https://3d-fab.ch/it/calculator/basic"
+    />
+    <changefreq>weekly</changefreq>
+    <priority>0.9</priority>
+  </url>
+  <url>
+    <loc>https://3d-fab.ch/it/calculator/advanced</loc>
+    <xhtml:link
+      rel="alternate"
+      hreflang="it"
+      href="https://3d-fab.ch/it/calculator/advanced"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="en"
+      href="https://3d-fab.ch/en/calculator/advanced"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="de"
+      href="https://3d-fab.ch/de/calculator/advanced"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="fr"
+      href="https://3d-fab.ch/fr/calculator/advanced"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="x-default"
+      href="https://3d-fab.ch/it/calculator/advanced"
+    />
+    <changefreq>weekly</changefreq>
+    <priority>0.8</priority>
+  </url>
+  <url>
+    <loc>https://3d-fab.ch/it/about</loc>
+    <xhtml:link rel="alternate" hreflang="it" href="https://3d-fab.ch/it/about" />
+    <xhtml:link rel="alternate" hreflang="en" href="https://3d-fab.ch/en/about" />
+    <xhtml:link rel="alternate" hreflang="de" href="https://3d-fab.ch/de/about" />
+    <xhtml:link rel="alternate" hreflang="fr" href="https://3d-fab.ch/fr/about" />
+    <xhtml:link
+      rel="alternate"
+      hreflang="x-default"
+      href="https://3d-fab.ch/it/about"
+    />
+    <changefreq>monthly</changefreq>
+    <priority>0.7</priority>
+  </url>
+  <url>
+    <loc>https://3d-fab.ch/it/contact</loc>
+    <xhtml:link
+      rel="alternate"
+      hreflang="it"
+      href="https://3d-fab.ch/it/contact"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="en"
+      href="https://3d-fab.ch/en/contact"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="de"
+      href="https://3d-fab.ch/de/contact"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="fr"
+      href="https://3d-fab.ch/fr/contact"
+    />
+    <xhtml:link
+      rel="alternate"
+      hreflang="x-default"
+      href="https://3d-fab.ch/it/contact"
+    />
+    <changefreq>monthly</changefreq>
+    <priority>0.7</priority>
+  </url>
+  <url>
+    <loc>https://3d-fab.ch/it/privacy</loc>
+    <xhtml:link rel="alternate" hreflang="it" href="https://3d-fab.ch/it/privacy" />
+    <xhtml:link rel="alternate" hreflang="en" href="https://3d-fab.ch/en/privacy" />
+    <xhtml:link rel="alternate" hreflang="de" href="https://3d-fab.ch/de/privacy" />
+    <xhtml:link rel="alternate" hreflang="fr" href="https://3d-fab.ch/fr/privacy" />
+    <xhtml:link
+      rel="alternate"
+      hreflang="x-default"
+      href="https://3d-fab.ch/it/privacy"
+    />
+    <changefreq>yearly</changefreq>
+    <priority>0.4</priority>
+  </url>
+  <url>
+    <loc>https://3d-fab.ch/it/terms</loc>
+    <xhtml:link rel="alternate" hreflang="it" href="https://3d-fab.ch/it/terms" />
+    <xhtml:link rel="alternate" hreflang="en" href="https://3d-fab.ch/en/terms" />
+    <xhtml:link rel="alternate" hreflang="de" href="https://3d-fab.ch/de/terms" />
+    <xhtml:link rel="alternate" hreflang="fr" href="https://3d-fab.ch/fr/terms" />
+    <xhtml:link rel="alternate" hreflang="x-default" href="https://3d-fab.ch/it/terms" />
+    <changefreq>yearly</changefreq>
+    <priority>0.4</priority>
+  </url>
+</urlset>
diff --git a/frontend/src/app/app.component.ts b/frontend/src/app/app.component.ts
index cb93b2a..53a2fdb 100644
--- a/frontend/src/app/app.component.ts
+++ b/frontend/src/app/app.component.ts
@@ -1,5 +1,6 @@
-import { Component } from '@angular/core';
+import { Component, inject } from '@angular/core';
 import { RouterOutlet } from '@angular/router';
+import { SeoService } from './core/services/seo.service';
 
 @Component({
   selector: 'app-root',
@@ -8,4 +9,6 @@ import { RouterOutlet } from '@angular/router';
   templateUrl: './app.component.html',
   styleUrl: './app.component.scss',
 })
-export class AppComponent {}
+export class AppComponent {
+  private readonly seoService = inject(SeoService);
+}
diff --git a/frontend/src/app/app.routes.ts b/frontend/src/app/app.routes.ts
index 2b5024f..c423e3b 100644
--- a/frontend/src/app/app.routes.ts
+++ b/frontend/src/app/app.routes.ts
@@ -5,6 +5,11 @@ const appChildRoutes: Routes = [
     path: '',
     loadComponent: () =>
       import('./features/home/home.component').then((m) => m.HomeComponent),
+    data: {
+      seoTitle: '3D fab | Stampa 3D su misura',
+      seoDescription:
+        'Servizio di stampa 3D con preventivo online immediato per prototipi, piccole serie e pezzi personalizzati.',
+    },
   },
   {
     path: 'calculator',
@@ -12,21 +17,42 @@ const appChildRoutes: Routes = [
       import('./features/calculator/calculator.routes').then(
         (m) => m.CALCULATOR_ROUTES,
       ),
+    data: {
+      seoTitle: 'Calcolatore preventivo stampa 3D | 3D fab',
+      seoDescription:
+        'Carica il file 3D e ottieni prezzo e tempi in pochi secondi con slicing reale.',
+    },
   },
   {
     path: 'shop',
     loadChildren: () =>
       import('./features/shop/shop.routes').then((m) => m.SHOP_ROUTES),
+    data: {
+      seoTitle: 'Shop 3D fab',
+      seoDescription:
+        'Catalogo prodotti stampati in 3D e soluzioni tecniche pronte all uso.',
+      seoRobots: 'noindex, nofollow',
+    },
   },
   {
     path: 'about',
     loadChildren: () =>
       import('./features/about/about.routes').then((m) => m.ABOUT_ROUTES),
+    data: {
+      seoTitle: 'Chi siamo | 3D fab',
+      seoDescription:
+        'Scopri il team 3D fab e il laboratorio di stampa 3D con sedi in Ticino e Bienne.',
+    },
   },
   {
     path: 'contact',
     loadChildren: () =>
       import('./features/contact/contact.routes').then((m) => m.CONTACT_ROUTES),
+    data: {
+      seoTitle: 'Contatti | 3D fab',
+      seoDescription:
+        'Contatta 3D fab per preventivi, supporto tecnico e richieste personalizzate di stampa 3D.',
+    },
   },
   {
     path: 'checkout/cad',
@@ -34,6 +60,10 @@ const appChildRoutes: Routes = [
       import('./features/checkout/checkout.component').then(
         (m) => m.CheckoutComponent,
       ),
+    data: {
+      seoTitle: 'Checkout | 3D fab',
+      seoRobots: 'noindex, nofollow',
+    },
   },
   {
     path: 'checkout',
@@ -41,16 +71,28 @@ const appChildRoutes: Routes = [
       import('./features/checkout/checkout.component').then(
         (m) => m.CheckoutComponent,
       ),
+    data: {
+      seoTitle: 'Checkout | 3D fab',
+      seoRobots: 'noindex, nofollow',
+    },
   },
   {
     path: 'order/:orderId',
     loadComponent: () =>
       import('./features/order/order.component').then((m) => m.OrderComponent),
+    data: {
+      seoTitle: 'Ordine | 3D fab',
+      seoRobots: 'noindex, nofollow',
+    },
   },
   {
     path: 'co/:orderId',
     loadComponent: () =>
       import('./features/order/order.component').then((m) => m.OrderComponent),
+    data: {
+      seoTitle: 'Ordine | 3D fab',
+      seoRobots: 'noindex, nofollow',
+    },
   },
   {
     path: '',
@@ -61,6 +103,10 @@ const appChildRoutes: Routes = [
     path: 'admin',
     loadChildren: () =>
       import('./features/admin/admin.routes').then((m) => m.ADMIN_ROUTES),
+    data: {
+      seoTitle: 'Admin | 3D fab',
+      seoRobots: 'noindex, nofollow',
+    },
   },
   {
     path: '**',
diff --git a/frontend/src/app/core/services/seo.service.ts b/frontend/src/app/core/services/seo.service.ts
new file mode 100644
index 0000000..ef26bde
--- /dev/null
+++ b/frontend/src/app/core/services/seo.service.ts
@@ -0,0 +1,129 @@
+import { DOCUMENT } from '@angular/common';
+import { Inject, Injectable } from '@angular/core';
+import { Title, Meta } from '@angular/platform-browser';
+import { ActivatedRouteSnapshot, NavigationEnd, Router } from '@angular/router';
+import { filter } from 'rxjs/operators';
+
+@Injectable({
+  providedIn: 'root',
+})
+export class SeoService {
+  private readonly defaultTitle = '3D fab | Stampa 3D su misura';
+  private readonly defaultDescription =
+    'Stampa 3D su misura con preventivo online immediato. Carica il file, scegli materiale e qualità, ricevi prezzo e tempi in pochi secondi.';
+  private readonly supportedLangs = new Set(['it', 'en', 'de', 'fr']);
+
+  constructor(
+    private router: Router,
+    private titleService: Title,
+    private metaService: Meta,
+    @Inject(DOCUMENT) private document: Document,
+  ) {
+    this.applyRouteSeo(this.router.routerState.snapshot.root);
+    this.router.events
+      .pipe(
+        filter(
+          (event): event is NavigationEnd => event instanceof NavigationEnd,
+        ),
+      )
+      .subscribe(() => {
+        this.applyRouteSeo(this.router.routerState.snapshot.root);
+      });
+  }
+
+  private applyRouteSeo(rootSnapshot: ActivatedRouteSnapshot): void {
+    const mergedData = this.getMergedRouteData(rootSnapshot);
+    const title = this.asString(mergedData['seoTitle']) ?? this.defaultTitle;
+    const description =
+      this.asString(mergedData['seoDescription']) ?? this.defaultDescription;
+    const robots = this.asString(mergedData['seoRobots']) ?? 'index, follow';
+
+    this.titleService.setTitle(title);
+    this.metaService.updateTag({ name: 'description', content: description });
+    this.metaService.updateTag({ name: 'robots', content: robots });
+    this.metaService.updateTag({ property: 'og:title', content: title });
+    this.metaService.updateTag({
+      property: 'og:description',
+      content: description,
+    });
+    this.metaService.updateTag({ property: 'og:type', content: 'website' });
+    this.metaService.updateTag({ name: 'twitter:card', content: 'summary' });
+
+    const cleanPath = this.getCleanPath(this.router.url);
+    const canonical = `${this.document.location.origin}${cleanPath}`;
+    this.metaService.updateTag({ property: 'og:url', content: canonical });
+    this.updateCanonicalTag(canonical);
+    this.updateLangAndAlternates(cleanPath);
+  }
+
+  private getMergedRouteData(
+    snapshot: ActivatedRouteSnapshot,
+  ): Record<string, unknown> {
+    const merged: Record<string, unknown> = {};
+    let cursor: ActivatedRouteSnapshot | null = snapshot;
+    while (cursor) {
+      Object.assign(merged, cursor.data ?? {});
+      cursor = cursor.firstChild;
+    }
+    return merged;
+  }
+
+  private asString(value: unknown): string | undefined {
+    return typeof value === 'string' ? value : undefined;
+  }
+
+  private getCleanPath(url: string): string {
+    const path = (url || '/').split('?')[0].split('#')[0];
+    return path || '/';
+  }
+
+  private updateCanonicalTag(url: string): void {
+    let link = this.document.head.querySelector(
+      'link[rel="canonical"]',
+    ) as HTMLLinkElement | null;
+    if (!link) {
+      link = this.document.createElement('link');
+      link.setAttribute('rel', 'canonical');
+      this.document.head.appendChild(link);
+    }
+    link.setAttribute('href', url);
+  }
+
+  private updateLangAndAlternates(path: string): void {
+    const segments = path.split('/').filter(Boolean);
+    const firstSegment = segments[0]?.toLowerCase();
+    const hasLang = Boolean(
+      firstSegment && this.supportedLangs.has(firstSegment),
+    );
+    const lang = hasLang ? firstSegment : 'it';
+    const suffixSegments = hasLang ? segments.slice(1) : segments;
+    const suffix =
+      suffixSegments.length > 0 ? `/${suffixSegments.join('/')}` : '';
+
+    this.document.documentElement.lang = lang;
+
+    this.document.head
+      .querySelectorAll('link[rel="alternate"][data-seo-managed="true"]')
+      .forEach((node) => node.remove());
+
+    for (const alt of ['it', 'en', 'de', 'fr']) {
+      this.appendAlternateLink(
+        alt,
+        `${this.document.location.origin}/${alt}${suffix}`,
+      );
+    }
+    this.appendAlternateLink(
+      'x-default',
+      `${this.document.location.origin}/it${suffix}`,
+    );
+  }
+
+  private appendAlternateLink(hreflang: string, href: string): void {
+    const link = this.document.createElement('link');
+    link.setAttribute('rel', 'alternate');
+    link.setAttribute('hreflang', hreflang);
+    link.setAttribute('href', href);
+    link.setAttribute('data-seo-managed', 'true');
+    this.document.head.appendChild(link);
+  }
+}
diff --git a/frontend/src/app/features/about/about.routes.ts b/frontend/src/app/features/about/about.routes.ts
index 0128c8e..3d7d210 100644
--- a/frontend/src/app/features/about/about.routes.ts
+++ b/frontend/src/app/features/about/about.routes.ts
@@ -2,5 +2,13 @@ import { Routes } from '@angular/router';
 import { AboutPageComponent } from './about-page.component';
 
 export const ABOUT_ROUTES: Routes = [
-  { path: '', component: AboutPageComponent },
+  {
+    path: '',
+    component: AboutPageComponent,
+    data: {
+      seoTitle: 'Chi siamo | 3D fab',
+      seoDescription:
+        'Siamo un laboratorio di stampa 3D orientato a prototipi, ricambi e produzioni su misura.',
+    },
+  },
 ];
diff --git a/frontend/src/app/features/calculator/calculator-page.component.html b/frontend/src/app/features/calculator/calculator-page.component.html
index 070b68d..8aab319 100644
--- a/frontend/src/app/features/calculator/calculator-page.component.html
+++ b/frontend/src/app/features/calculator/calculator-page.component.html
@@ -24,7 +24,7 @@
             class="mode-option"
             [class.active]="mode() === 'easy'"
             [class.disabled]="cadSessionLocked()"
-            (click)="!cadSessionLocked() && mode.set('easy')"
+            (click)="switchMode('easy')"
           >
             {{ "CALC.MODE_EASY" | translate }}
           </div>
@@ -32,7 +32,7 @@
             class="mode-option"
             [class.active]="mode() === 'advanced'"
             [class.disabled]="cadSessionLocked()"
-            (click)="!cadSessionLocked() && mode.set('advanced')"
+            (click)="switchMode('advanced')"
           >
             {{ "CALC.MODE_ADVANCED" | translate }}
           </div>
@@ -45,6 +45,8 @@
           [loading]="loading()"
           [uploadProgress]="uploadProgress()"
           (submitRequest)="onCalculate($event)"
+          (itemQuantityChange)="onUploadItemQuantityChange($event)"
+          (printSettingsChange)="onUploadPrintSettingsChange($event)"
         ></app-upload-form>
       </app-card>
     </div>
@@ -64,8 +66,10 @@
       } @else if (result()) {
         <app-quote-result
           [result]="result()!"
+          [recalculationRequired]="requiresRecalculation()"
           (consult)="onConsult()"
           (proceed)="onProceed()"
+          (itemQuantityPreviewChange)="onQuoteItemQuantityPreviewChange($event)"
           (itemChange)="onItemChange($event)"
         ></app-quote-result>
       } @else if (isZeroQuoteError()) {
diff --git a/frontend/src/app/features/calculator/calculator-page.component.ts b/frontend/src/app/features/calculator/calculator-page.component.ts
index 6e56a60..10b2aea 100644
--- a/frontend/src/app/features/calculator/calculator-page.component.ts
+++ b/frontend/src/app/features/calculator/calculator-page.component.ts
@@ -42,7 +42,7 @@ import { LanguageService } from '../../core/services/language.service';
   styleUrl: './calculator-page.component.scss',
 })
 export class CalculatorPageComponent implements OnInit {
-  mode = signal<any>('easy');
+  mode = signal<'easy' | 'advanced'>('easy');
   step = signal<'upload' | 'quote' | 'details' | 'success'>('upload');
 
   loading = signal(false);
@@ -56,6 +56,17 @@ export class CalculatorPageComponent implements OnInit {
   );
 
   orderSuccess = signal(false);
+  requiresRecalculation = signal(false);
+  private baselinePrintSettings: {
+    mode: 'easy' | 'advanced';
+    material: string;
+    quality: string;
+    nozzleDiameter: number;
+    layerHeight: number;
+    infillDensity: number;
+    infillPattern: string;
+    supportEnabled: boolean;
+  } | null = null;
 
   @ViewChild('uploadForm') uploadForm!: UploadFormComponent;
   @ViewChild('resultCol') resultCol!: ElementRef;
@@ -101,6 +112,10 @@ export class CalculatorPageComponent implements OnInit {
         this.error.set(false);
         this.errorKey.set('CALC.ERROR_GENERIC');
         this.result.set(result);
+        this.baselinePrintSettings = this.toTrackedSettingsFromSession(
+          data.session,
+        );
+        this.requiresRecalculation.set(false);
         const isCadSession = data?.session?.status === 'CAD_ACTIVE';
         this.cadSessionLocked.set(isCadSession);
         this.step.set('quote');
@@ -238,6 +253,8 @@ export class CalculatorPageComponent implements OnInit {
           this.error.set(false);
           this.errorKey.set('CALC.ERROR_GENERIC');
           this.result.set(res);
+          this.baselinePrintSettings = this.toTrackedSettingsFromRequest(req);
+          this.requiresRecalculation.set(false);
           this.loading.set(false);
           this.uploadProgress.set(100);
           this.step.set('quote');
@@ -295,9 +312,10 @@ export class CalculatorPageComponent implements OnInit {
     index: number;
     fileName: string;
     quantity: number;
+    source?: 'left' | 'right';
   }) {
     // 1. Update local form for consistency (UI feedback)
-    if (this.uploadForm) {
+    if (event.source !== 'left' && this.uploadForm) {
       this.uploadForm.updateItemQuantityByIndex(event.index, event.quantity);
       this.uploadForm.updateItemQuantityByName(event.fileName, event.quantity);
     }
@@ -340,6 +358,33 @@ export class CalculatorPageComponent implements OnInit {
     }
   }
 
+  onUploadItemQuantityChange(event: {
+    index: number;
+    fileName: string;
+    quantity: number;
+  }) {
+    const resultItems = this.result()?.items || [];
+    const byIndex = resultItems[event.index];
+    const byName = resultItems.find((item) => item.fileName === event.fileName);
+    const id = byIndex?.id ?? byName?.id;
+
+    this.onItemChange({
+      ...event,
+      id,
+      source: 'left',
+    });
+  }
+
+  onQuoteItemQuantityPreviewChange(event: {
+    index: number;
+    fileName: string;
+    quantity: number;
+  }) {
+    if (!this.uploadForm) return;
+    this.uploadForm.updateItemQuantityByIndex(event.index, event.quantity);
+    this.uploadForm.updateItemQuantityByName(event.fileName, event.quantity);
+  }
+
   onSubmitOrder(orderData: any) {
     console.log('Order Submitted:', orderData);
     this.orderSuccess.set(true);
@@ -349,15 +394,37 @@ export class CalculatorPageComponent implements OnInit {
   onNewQuote() {
     this.step.set('upload');
     this.result.set(null);
+    this.requiresRecalculation.set(false);
+    this.baselinePrintSettings = null;
     this.cadSessionLocked.set(false);
     this.orderSuccess.set(false);
-    this.mode.set('easy'); // Reset to default
+    this.switchMode('easy'); // Reset to default and sync URL
   }
 
   private currentRequest: QuoteRequest | null = null;
 
+  onUploadPrintSettingsChange(settings: {
+    mode: 'easy' | 'advanced';
+    material: string;
+    quality: string;
+    nozzleDiameter: number;
+    layerHeight: number;
+    infillDensity: number;
+    infillPattern: string;
+    supportEnabled: boolean;
+  }) {
+    if (!this.result()) return;
+    if (!this.baselinePrintSettings) return;
+    this.requiresRecalculation.set(
+      !this.sameTrackedSettings(this.baselinePrintSettings, settings),
+    );
+  }
+
   onConsult() {
-    if (!this.currentRequest) {
+    const currentFormRequest = this.uploadForm?.getCurrentRequestDraft();
+    const req = currentFormRequest ?? this.currentRequest;
+
+    if (!req) {
       this.router.navigate([
         '/',
         this.languageService.selectedLang(),
@@ -366,7 +433,6 @@ export class CalculatorPageComponent implements OnInit {
       return;
     }
 
-    const req = this.currentRequest;
     let details = `Richiesta Preventivo:\n`;
     details += `- Materiale: ${req.material}\n`;
     details += `- Qualità: ${req.quality}\n`;
@@ -411,5 +477,126 @@ export class CalculatorPageComponent implements OnInit {
     this.errorKey.set(key);
     this.error.set(true);
     this.result.set(null);
+    this.requiresRecalculation.set(false);
+    this.baselinePrintSettings = null;
+  }
+
+  switchMode(nextMode: 'easy' | 'advanced'): void {
+    if (this.cadSessionLocked()) return;
+
+    const targetPath = nextMode === 'easy' ? 'basic' : 'advanced';
+    const currentPath = this.route.snapshot.routeConfig?.path;
+
+    this.mode.set(nextMode);
+
+    if (currentPath === targetPath) {
+      return;
+    }
+
+    this.router.navigate(['..', targetPath], {
+      relativeTo: this.route,
+      queryParamsHandling: 'preserve',
+    });
+  }
+
+  private toTrackedSettingsFromRequest(req: QuoteRequest): {
+    mode: 'easy' | 'advanced';
+    material: string;
+    quality: string;
+    nozzleDiameter: number;
+    layerHeight: number;
+    infillDensity: number;
+    infillPattern: string;
+    supportEnabled: boolean;
+  } {
+    return {
+      mode: req.mode,
+      material: this.normalizeString(req.material || 'PLA'),
+      quality: this.normalizeString(req.quality || 'standard'),
+      nozzleDiameter: this.normalizeNumber(req.nozzleDiameter, 0.4, 2),
+      layerHeight: this.normalizeNumber(req.layerHeight, 0.2, 3),
+      infillDensity: this.normalizeNumber(req.infillDensity, 20, 2),
+      infillPattern: this.normalizeString(req.infillPattern || 'grid'),
+      supportEnabled: Boolean(req.supportEnabled),
+    };
+  }
+
+  private toTrackedSettingsFromSession(session: any): {
+    mode: 'easy' | 'advanced';
+    material: string;
+    quality: string;
+    nozzleDiameter: number;
+    layerHeight: number;
+    infillDensity: number;
+    infillPattern: string;
+    supportEnabled: boolean;
+  } {
+    const layer = this.normalizeNumber(session?.layerHeightMm, 0.2, 3);
+    return {
+      mode: this.mode(),
+      material: this.normalizeString(session?.materialCode || 'PLA'),
+      quality:
+        layer >= 0.24 ? 'draft' : layer <= 0.12 ? 'extra_fine' : 'standard',
+      nozzleDiameter: this.normalizeNumber(session?.nozzleDiameterMm, 0.4, 2),
+      layerHeight: layer,
+      infillDensity: this.normalizeNumber(session?.infillPercent, 20, 2),
+      infillPattern: this.normalizeString(session?.infillPattern || 'grid'),
+      supportEnabled: Boolean(session?.supportsEnabled),
+    };
+  }
+
+  private sameTrackedSettings(
+    a: {
+      mode: 'easy' | 'advanced';
+      material: string;
+      quality: string;
+      nozzleDiameter: number;
+      layerHeight: number;
+      infillDensity: number;
+      infillPattern: string;
+      supportEnabled: boolean;
+    },
+    b: {
+      mode: 'easy' | 'advanced';
+      material: string;
+      quality: string;
+      nozzleDiameter: number;
+      layerHeight: number;
+      infillDensity: number;
+      infillPattern: string;
+      supportEnabled: boolean;
+    },
+  ): boolean {
+    return (
+      a.mode === b.mode &&
+      a.material === this.normalizeString(b.material) &&
+      a.quality === this.normalizeString(b.quality) &&
+      Math.abs(
+        a.nozzleDiameter - this.normalizeNumber(b.nozzleDiameter, 0.4, 2),
+      ) < 0.0001 &&
+      Math.abs(a.layerHeight - this.normalizeNumber(b.layerHeight, 0.2, 3)) <
+        0.0001 &&
+      Math.abs(a.infillDensity - this.normalizeNumber(b.infillDensity, 20, 2)) <
+        0.0001 &&
+      a.infillPattern === this.normalizeString(b.infillPattern) &&
+      a.supportEnabled === Boolean(b.supportEnabled)
+    );
+  }
+
+  private normalizeString(value: string): string {
+    return String(value || '')
+      .trim()
+      .toLowerCase();
+  }
+
+  private normalizeNumber(
+    value: unknown,
+    fallback: number,
+    decimals: number,
+  ): number {
+    const numeric = Number(value);
+    const resolved = Number.isFinite(numeric) ? numeric : fallback;
+    const factor = 10 ** decimals;
+    return Math.round(resolved * factor) / factor;
   }
 }
diff --git a/frontend/src/app/features/calculator/calculator.routes.ts b/frontend/src/app/features/calculator/calculator.routes.ts
index 5a670cd..134457b 100644
--- a/frontend/src/app/features/calculator/calculator.routes.ts
+++ b/frontend/src/app/features/calculator/calculator.routes.ts
@@ -3,10 +3,24 @@ import { CalculatorPageComponent } from './calculator-page.component';
 
 export const CALCULATOR_ROUTES: Routes = [
   { path: '', redirectTo: 'basic', pathMatch: 'full' },
-  { path: 'basic', component: CalculatorPageComponent, data: { mode: 'easy' } },
+  {
+    path: 'basic',
+    component: CalculatorPageComponent,
+    data: {
+      mode: 'easy',
+      seoTitle: 'Calcolatore stampa 3D base | 3D fab',
+      seoDescription:
+        'Calcola rapidamente il prezzo della tua stampa 3D in modalita base.',
+    },
+  },
   {
     path: 'advanced',
     component: CalculatorPageComponent,
-    data: { mode: 'advanced' },
+    data: {
+      mode: 'advanced',
+      seoTitle: 'Calcolatore stampa 3D avanzato | 3D fab',
+      seoDescription:
+        'Configura parametri avanzati e ottieni un preventivo preciso con slicing reale.',
+    },
   },
 ];
diff --git a/frontend/src/app/features/calculator/components/quote-result/quote-result.component.html b/frontend/src/app/features/calculator/components/quote-result/quote-result.component.html
index d7141b7..2c81b84 100644
--- a/frontend/src/app/features/calculator/components/quote-result/quote-result.component.html
+++ b/frontend/src/app/features/calculator/components/quote-result/quote-result.component.html
@@ -45,6 +45,12 @@
       <p>{{ result().notes }}</p>
     </div>
   }
+  @if (recalculationRequired()) {
+    <div class="recalc-banner">
+      Hai modificato i parametri di stampa. Ricalcola il preventivo prima di
+      procedere con l'ordine.
+    </div>
+  }
 
   <div class="divider"></div>
 
@@ -104,7 +110,10 @@
 
     <div class="actions-right">
       @if (!hasQuantityOverLimit()) {
-        <app-button (click)="proceed.emit()">
+        <app-button
+          [disabled]="recalculationRequired()"
+          (click)="proceed.emit()"
+        >
           {{ "QUOTE.PROCEED_ORDER" | translate }}
         </app-button>
       } @else {
@@ -112,6 +121,11 @@
           "QUOTE.MAX_QTY_NOTICE" | translate: { max: directOrderLimit }
         }}</small>
       }
+      @if (recalculationRequired()) {
+        <small class="limit-note">
+          Ricalcola il preventivo per riattivare il checkout.
+        </small>
+      }
     </div>
   </div>
 </app-card>
diff --git a/frontend/src/app/features/calculator/components/quote-result/quote-result.component.scss b/frontend/src/app/features/calculator/components/quote-result/quote-result.component.scss
index 38913fa..b4e94b2 100644
--- a/frontend/src/app/features/calculator/components/quote-result/quote-result.component.scss
+++ b/frontend/src/app/features/calculator/components/quote-result/quote-result.component.scss
@@ -184,3 +184,14 @@
     white-space: pre-wrap; /* Preserve line breaks */
   }
 }
+
+.recalc-banner {
+  margin-top: var(--space-4);
+  margin-bottom: var(--space-4);
+  padding: var(--space-3);
+  border: 1px solid #f0c95a;
+  background: #fff8e1;
+  border-radius: var(--radius-md);
+  color: #6f5b1a;
+  font-size: 0.9rem;
+}
diff --git a/frontend/src/app/features/calculator/components/quote-result/quote-result.component.ts b/frontend/src/app/features/calculator/components/quote-result/quote-result.component.ts
index 5da71ec..ce0df34 100644
--- a/frontend/src/app/features/calculator/components/quote-result/quote-result.component.ts
+++ b/frontend/src/app/features/calculator/components/quote-result/quote-result.component.ts
@@ -35,6 +35,7 @@ export class QuoteResultComponent implements OnDestroy {
   readonly quantityAutoRefreshMs = 2000;
 
   result = input.required<QuoteResult>();
+  recalculationRequired = input<boolean>(false);
   consult = output<void>();
   proceed = output<void>();
   itemChange = output<{
@@ -43,6 +44,12 @@ export class QuoteResultComponent implements OnDestroy {
     fileName: string;
     quantity: number;
   }>();
+  itemQuantityPreviewChange = output<{
+    id?: string;
+    index: number;
+    fileName: string;
+    quantity: number;
+  }>();
 
   // Local mutable state for items to handle quantity changes
   items = signal<QuoteItem[]>([]);
@@ -87,6 +94,13 @@ export class QuoteResultComponent implements OnDestroy {
       return updated;
     });
 
+    this.itemQuantityPreviewChange.emit({
+      id: item.id,
+      index,
+      fileName: item.fileName,
+      quantity: normalizedQty,
+    });
+
     this.scheduleQuantityRefresh(index, key);
   }
 
diff --git a/frontend/src/app/features/calculator/components/upload-form/upload-form.component.ts b/frontend/src/app/features/calculator/components/upload-form/upload-form.component.ts
index 30d323e..6b9d46c 100644
--- a/frontend/src/app/features/calculator/components/upload-form/upload-form.component.ts
+++ b/frontend/src/app/features/calculator/components/upload-form/upload-form.component.ts
@@ -62,6 +62,21 @@ export class UploadFormComponent implements OnInit {
   loading = input<boolean>(false);
   uploadProgress = input<number>(0);
   submitRequest = output<QuoteRequest>();
+  itemQuantityChange = output<{
+    index: number;
+    fileName: string;
+    quantity: number;
+  }>();
+  printSettingsChange = output<{
+    mode: 'easy' | 'advanced';
+    material: string;
+    quality: string;
+    nozzleDiameter: number;
+    layerHeight: number;
+    infillDensity: number;
+    infillPattern: string;
+    supportEnabled: boolean;
+  }>();
 
   private estimator = inject(QuoteEstimatorService);
   private fb = inject(FormBuilder);
@@ -81,6 +96,8 @@ export class UploadFormComponent implements OnInit {
 
   // Store full material options to lookup variants/colors if needed later
   private fullMaterialOptions: MaterialOption[] = [];
+  private allLayerHeights: SimpleOption[] = [];
+  private layerHeightsByNozzle: Record<string, SimpleOption[]> = {};
   private isPatchingSettings = false;
 
   // Computed variants for valid material
@@ -141,6 +158,14 @@ export class UploadFormComponent implements OnInit {
       if (this.mode() !== 'easy' || this.isPatchingSettings) return;
       this.applyAdvancedPresetFromQuality(quality);
     });
+    this.form.get('nozzleDiameter')?.valueChanges.subscribe((nozzle) => {
+      if (this.isPatchingSettings) return;
+      this.updateLayerHeightOptionsForNozzle(nozzle, true);
+    });
+    this.form.valueChanges.subscribe(() => {
+      if (this.isPatchingSettings) return;
+      this.emitPrintSettingsChange();
+    });
 
     effect(() => {
       this.applySettingsLock(this.lockedSettings());
@@ -187,6 +212,7 @@ export class UploadFormComponent implements OnInit {
 
     const preset = presets[normalized] || presets['standard'];
     this.form.patchValue(preset, { emitEvent: false });
+    this.updateLayerHeightOptionsForNozzle(preset.nozzleDiameter, true);
   }
 
   ngOnInit() {
@@ -204,9 +230,19 @@ export class UploadFormComponent implements OnInit {
         this.infillPatterns.set(
           options.infillPatterns.map((p) => ({ label: p.label, value: p.id })),
         );
-        this.layerHeights.set(
-          options.layerHeights.map((l) => ({ label: l.label, value: l.value })),
-        );
+        this.allLayerHeights = options.layerHeights.map((l) => ({
+          label: l.label,
+          value: l.value,
+        }));
+        this.layerHeightsByNozzle = {};
+        (options.layerHeightsByNozzle || []).forEach((entry) => {
+          this.layerHeightsByNozzle[this.toNozzleKey(entry.nozzleDiameter)] =
+            entry.layerHeights.map((layer) => ({
+              label: layer.label,
+              value: layer.value,
+            }));
+        });
+        this.layerHeights.set(this.allLayerHeights);
         this.nozzleDiameters.set(
           options.nozzleDiameters.map((n) => ({
             label: n.label,
@@ -231,6 +267,11 @@ export class UploadFormComponent implements OnInit {
             value: 'standard',
           },
         ]);
+        this.allLayerHeights = [{ label: '0.20 mm', value: 0.2 }];
+        this.layerHeightsByNozzle = {
+          [this.toNozzleKey(0.4)]: this.allLayerHeights,
+        };
+        this.layerHeights.set(this.allLayerHeights);
         this.nozzleDiameters.set([{ label: '0.4 mm', value: 0.4 }]);
         this.setDefaults();
       },
@@ -240,7 +281,16 @@ export class UploadFormComponent implements OnInit {
   private setDefaults() {
     // Set Defaults if available
     if (this.materials().length > 0 && !this.form.get('material')?.value) {
-      this.form.get('material')?.setValue(this.materials()[0].value);
+      const exactPla = this.materials().find(
+        (m) => typeof m.value === 'string' && m.value.toUpperCase() === 'PLA',
+      );
+      const anyPla = this.materials().find(
+        (m) =>
+          typeof m.value === 'string' &&
+          m.value.toUpperCase().startsWith('PLA'),
+      );
+      const preferredMaterial = exactPla ?? anyPla ?? this.materials()[0];
+      this.form.get('material')?.setValue(preferredMaterial.value);
     }
     if (this.qualities().length > 0 && !this.form.get('quality')?.value) {
       // Try to find 'standard' or use first
@@ -255,18 +305,20 @@ export class UploadFormComponent implements OnInit {
     ) {
       this.form.get('nozzleDiameter')?.setValue(0.4); // Prefer 0.4
     }
-    if (
-      this.layerHeights().length > 0 &&
-      !this.form.get('layerHeight')?.value
-    ) {
-      this.form.get('layerHeight')?.setValue(0.2); // Prefer 0.2
-    }
+
+    this.updateLayerHeightOptionsForNozzle(
+      this.form.get('nozzleDiameter')?.value,
+      true,
+    );
+
     if (
       this.infillPatterns().length > 0 &&
       !this.form.get('infillPattern')?.value
     ) {
       this.form.get('infillPattern')?.setValue(this.infillPatterns()[0].value);
     }
+
+    this.emitPrintSettingsChange();
   }
 
   onFilesDropped(newFiles: File[]) {
@@ -369,7 +421,15 @@ export class UploadFormComponent implements OnInit {
     const input = event.target as HTMLInputElement;
     const parsed = parseInt(input.value, 10);
     const quantity = Number.isFinite(parsed) ? parsed : 1;
+    const currentItem = this.items()[index];
+    if (!currentItem) return;
+    const normalizedQty = this.normalizeQuantity(quantity);
     this.updateItemQuantityByIndex(index, quantity);
+    this.itemQuantityChange.emit({
+      index,
+      fileName: currentItem.file.name,
+      quantity: normalizedQty,
+    });
   }
 
   updateItemColor(
@@ -514,6 +574,11 @@ export class UploadFormComponent implements OnInit {
     this.isPatchingSettings = true;
     this.form.patchValue(patch, { emitEvent: false });
     this.isPatchingSettings = false;
+    this.updateLayerHeightOptionsForNozzle(
+      this.form.get('nozzleDiameter')?.value,
+      true,
+    );
+    this.emitPrintSettingsChange();
   }
 
   onSubmit() {
@@ -561,6 +626,86 @@ export class UploadFormComponent implements OnInit {
     return (fileName || '').split(/[\\/]/).pop()?.trim().toLowerCase() ?? '';
   }
 
+  private updateLayerHeightOptionsForNozzle(
+    nozzleValue: unknown,
+    preserveCurrent: boolean,
+  ): void {
+    const key = this.toNozzleKey(nozzleValue);
+    const nozzleSpecific = this.layerHeightsByNozzle[key] || [];
+    const available =
+      nozzleSpecific.length > 0 ? nozzleSpecific : this.allLayerHeights;
+    this.layerHeights.set(available);
+
+    const control = this.form.get('layerHeight');
+    if (!control) return;
+
+    const currentValue = Number(control.value);
+    const currentAllowed = available.some(
+      (option) => Math.abs(Number(option.value) - currentValue) < 0.0001,
+    );
+    if (preserveCurrent && currentAllowed) {
+      return;
+    }
+
+    const preferred = available.find(
+      (option) => Math.abs(Number(option.value) - 0.2) < 0.0001,
+    );
+    const next = preferred ?? available[0];
+    if (next) {
+      control.setValue(next.value, { emitEvent: false });
+    }
+  }
+
+  private toNozzleKey(value: unknown): string {
+    const numeric = Number(value);
+    if (!Number.isFinite(numeric)) return '';
+    return numeric.toFixed(2);
+  }
+
+  getCurrentRequestDraft(): QuoteRequest | null {
+    if (this.items().length === 0) return null;
+    const raw = this.form.getRawValue();
+    return {
+      items: this.items(),
+      material: raw.material,
+      quality: raw.quality,
+      notes: raw.notes,
+      infillDensity: raw.infillDensity,
+      infillPattern: raw.infillPattern,
+      supportEnabled: raw.supportEnabled,
+      layerHeight: raw.layerHeight,
+      nozzleDiameter: raw.nozzleDiameter,
+      mode: this.mode(),
+    };
+  }
+
+  getCurrentPrintSettings(): {
+    mode: 'easy' | 'advanced';
+    material: string;
+    quality: string;
+    nozzleDiameter: number;
+    layerHeight: number;
+    infillDensity: number;
+    infillPattern: string;
+    supportEnabled: boolean;
+  } {
+    const raw = this.form.getRawValue();
+    return {
+      mode: this.mode(),
+      material: String(raw.material || 'PLA'),
+      quality: String(raw.quality || 'standard'),
+      nozzleDiameter: Number(raw.nozzleDiameter ?? 0.4),
+      layerHeight: Number(raw.layerHeight ?? 0.2),
+      infillDensity: Number(raw.infillDensity ?? 20),
+      infillPattern: String(raw.infillPattern || 'grid'),
+      supportEnabled: Boolean(raw.supportEnabled),
+    };
+  }
+
+  private emitPrintSettingsChange(): void {
+    this.printSettingsChange.emit(this.getCurrentPrintSettings());
+  }
+
   private applySettingsLock(locked: boolean): void {
     const controlsToLock = [
       'material',
diff --git a/frontend/src/app/features/calculator/services/quote-estimator.service.ts b/frontend/src/app/features/calculator/services/quote-estimator.service.ts
index 7c72852..fed6db7 100644
--- a/frontend/src/app/features/calculator/services/quote-estimator.service.ts
+++ b/frontend/src/app/features/calculator/services/quote-estimator.service.ts
@@ -102,12 +102,18 @@ export interface NumericOption {
   label: string;
 }
 
+export interface NozzleLayerHeightsOption {
+  nozzleDiameter: number;
+  layerHeights: NumericOption[];
+}
+
 export interface OptionsResponse {
   materials: MaterialOption[];
   qualities: QualityOption[];
   infillPatterns: InfillOption[];
   layerHeights: NumericOption[];
   nozzleDiameters: NumericOption[];
+  layerHeightsByNozzle?: NozzleLayerHeightsOption[];
 }
 
 // UI Option for Select Component
diff --git a/frontend/src/app/features/contact/contact.routes.ts b/frontend/src/app/features/contact/contact.routes.ts
index f8ef5c5..6ee01b5 100644
--- a/frontend/src/app/features/contact/contact.routes.ts
+++ b/frontend/src/app/features/contact/contact.routes.ts
@@ -5,5 +5,10 @@ export const CONTACT_ROUTES: Routes = [
     path: '',
     loadComponent: () =>
       import('./contact-page.component').then((m) => m.ContactPageComponent),
+    data: {
+      seoTitle: 'Contatti | 3D fab',
+      seoDescription:
+        'Richiedi informazioni, preventivi personalizzati o supporto per progetti di stampa 3D.',
+    },
   },
 ];
diff --git a/frontend/src/app/features/home/home.component.html b/frontend/src/app/features/home/home.component.html
index 2255de4..9284fdf 100644
--- a/frontend/src/app/features/home/home.component.html
+++ b/frontend/src/app/features/home/home.component.html
@@ -37,28 +37,40 @@
       <div class="cap-cards">
         <app-card>
           <div class="card-image-placeholder">
-            <img src="assets/images/home/prototipi.jpg" alt="" />
+            <img
+              src="assets/images/home/prototipi.jpg"
+              [attr.alt]="'HOME.CAP_1_TITLE' | translate"
+            />
           </div>
           <h3>{{ "HOME.CAP_1_TITLE" | translate }}</h3>
           <p class="text-muted">{{ "HOME.CAP_1_TEXT" | translate }}</p>
         </app-card>
         <app-card>
           <div class="card-image-placeholder">
-            <img src="assets/images/home/original-vs-3dprinted.jpg" alt="" />
+            <img
+              src="assets/images/home/original-vs-3dprinted.jpg"
+              [attr.alt]="'HOME.CAP_2_TITLE' | translate"
+            />
           </div>
           <h3>{{ "HOME.CAP_2_TITLE" | translate }}</h3>
           <p class="text-muted">{{ "HOME.CAP_2_TEXT" | translate }}</p>
         </app-card>
         <app-card>
           <div class="card-image-placeholder">
-            <img src="assets/images/home/serie.jpg" alt="" />
+            <img
+              src="assets/images/home/serie.jpg"
+              [attr.alt]="'HOME.CAP_3_TITLE' | translate"
+            />
           </div>
           <h3>{{ "HOME.CAP_3_TITLE" | translate }}</h3>
           <p class="text-muted">{{ "HOME.CAP_3_TEXT" | translate }}</p>
         </app-card>
         <app-card>
           <div class="card-image-placeholder">
-            <img src="assets/images/home/cad.jpg" alt="" />
+            <img
+              src="assets/images/home/cad.jpg"
+              [attr.alt]="'HOME.CAP_4_TITLE' | translate"
+            />
           </div>
           <h3>{{ "HOME.CAP_4_TITLE" | translate }}</h3>
           <p class="text-muted">{{ "HOME.CAP_4_TEXT" | translate }}</p>
diff --git a/frontend/src/app/features/legal/legal.routes.ts b/frontend/src/app/features/legal/legal.routes.ts
index 78cc23e..274bfd7 100644
--- a/frontend/src/app/features/legal/legal.routes.ts
+++ b/frontend/src/app/features/legal/legal.routes.ts
@@ -5,10 +5,20 @@ export const LEGAL_ROUTES: Routes = [
     path: 'privacy',
     loadComponent: () =>
       import('./privacy/privacy.component').then((m) => m.PrivacyComponent),
+    data: {
+      seoTitle: 'Privacy Policy | 3D fab',
+      seoDescription:
+        'Informativa privacy di 3D fab: trattamento dati, finalita e contatti.',
+    },
   },
   {
     path: 'terms',
     loadComponent: () =>
       import('./terms/terms.component').then((m) => m.TermsComponent),
+    data: {
+      seoTitle: 'Termini e condizioni | 3D fab',
+      seoDescription:
+        'Termini e condizioni del servizio di stampa 3D e del calcolatore preventivi.',
+    },
   },
 ];
diff --git a/frontend/src/app/features/shop/shop.routes.ts b/frontend/src/app/features/shop/shop.routes.ts
index 22a7fb3..b94949b 100644
--- a/frontend/src/app/features/shop/shop.routes.ts
+++ b/frontend/src/app/features/shop/shop.routes.ts
@@ -3,6 +3,22 @@ import { ShopPageComponent } from './shop-page.component';
 import { ProductDetailComponent } from './product-detail.component';
 
 export const SHOP_ROUTES: Routes = [
-  { path: '', component: ShopPageComponent },
-  { path: ':id', component: ProductDetailComponent },
+  {
+    path: '',
+    component: ShopPageComponent,
+    data: {
+      seoTitle: 'Shop 3D fab',
+      seoDescription:
+        'Lo shop 3D fab e in allestimento. Intanto puoi usare il calcolatore per ottenere un preventivo.',
+      seoRobots: 'noindex, nofollow',
+    },
+  },
+  {
+    path: ':id',
+    component: ProductDetailComponent,
+    data: {
+      seoTitle: 'Prodotto | 3D fab',
+      seoRobots: 'noindex, nofollow',
+    },
+  },
 ];
diff --git a/frontend/src/index.html b/frontend/src/index.html
index 91a4429..140c33c 100644
--- a/frontend/src/index.html
+++ b/frontend/src/index.html
@@ -2,8 +2,12 @@
 <html lang="it">
   <head>
     <meta charset="utf-8" />
-    <meta name="robots" content="noindex, nofollow" />
-    <title>3D fab</title>
+    <title>3D fab | Stampa 3D su misura</title>
+    <meta
+      name="description"
+      content="Stampa 3D su misura con preventivo online immediato. Carica il file, scegli materiale e qualità, ricevi prezzo e tempi in pochi secondi."
+    />
+    <meta name="robots" content="index, follow" />
     <base href="/" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <link rel="icon" type="image/png" href="assets/images/Fav-icon.png" />