feat(inventory): Charge einbuchen (addBatch) (#5)

StockBatch als Child-Entity im Stock-Aggregat mit BatchReference
(batchId + batchType), Quantity, ExpiryDate und Status AVAILABLE.
POST /api/inventory/stocks/{stockId}/batches → 201.

backend/src/main/java/de/effigenix/application/inventory/AddStockBatch.java

@@ -0,0 +1,53 @@
+package de.effigenix.application.inventory;
+
+import de.effigenix.application.inventory.command.AddStockBatchCommand;
+import de.effigenix.domain.inventory.*;
+import de.effigenix.shared.common.Result;
+import org.springframework.transaction.annotation.Transactional;
+
+@Transactional
+public class AddStockBatch {
+
+    private final StockRepository stockRepository;
+
+    public AddStockBatch(StockRepository stockRepository) {
+        this.stockRepository = stockRepository;
+    }
+
+    public Result<StockError, StockBatch> execute(AddStockBatchCommand cmd) {
+        // 1. Stock laden
+        Stock stock;
+        switch (stockRepository.findById(StockId.of(cmd.stockId()))) {
+            case Result.Failure(var err) ->
+                { return Result.failure(new StockError.RepositoryFailure(err.message())); }
+            case Result.Success(var opt) -> {
+                if (opt.isEmpty()) {
+                    return Result.failure(new StockError.StockNotFound(cmd.stockId()));
+                }
+                stock = opt.get();
+            }
+        }
+
+        // 2. Batch hinzufügen (Domain validiert)
+        var draft = new StockBatchDraft(
+                cmd.batchId(), cmd.batchType(),
+                cmd.quantityAmount(), cmd.quantityUnit(),
+                cmd.expiryDate()
+        );
+
+        StockBatch batch;
+        switch (stock.addBatch(draft)) {
+            case Result.Failure(var err) -> { return Result.failure(err); }
+            case Result.Success(var val) -> batch = val;
+        }
+
+        // 3. Stock speichern
+        switch (stockRepository.save(stock)) {
+            case Result.Failure(var err) ->
+                { return Result.failure(new StockError.RepositoryFailure(err.message())); }
+            case Result.Success(var ignored) -> { }
+        }
+
+        return Result.success(batch);
+    }
+}

backend/src/main/java/de/effigenix/application/inventory/command/AddStockBatchCommand.java

@@ -0,0 +1,10 @@
+package de.effigenix.application.inventory.command;
+
+public record AddStockBatchCommand(
+        String stockId,
+        String batchId,
+        String batchType,
+        String quantityAmount,
+        String quantityUnit,
+        String expiryDate
+) {}

backend/src/main/java/de/effigenix/domain/inventory/BatchReference.java

@@ -0,0 +1,29 @@
+package de.effigenix.domain.inventory;
+
+import de.effigenix.shared.common.Result;
+
+import java.util.Objects;
+
+public record BatchReference(String batchId, BatchType batchType) {
+
+    public BatchReference {
+        Objects.requireNonNull(batchId, "batchId must not be null");
+        Objects.requireNonNull(batchType, "batchType must not be null");
+    }
+
+    public static Result<StockError, BatchReference> of(String batchId, String batchType) {
+        if (batchId == null || batchId.isBlank()) {
+            return Result.failure(new StockError.InvalidBatchReference("batchId must not be blank"));
+        }
+
+        BatchType type;
+        try {
+            type = BatchType.valueOf(batchType);
+        } catch (IllegalArgumentException | NullPointerException e) {
+            return Result.failure(new StockError.InvalidBatchReference(
+                    "Invalid batchType: " + batchType + ". Allowed values: PRODUCED, PURCHASED"));
+        }
+
+        return Result.success(new BatchReference(batchId, type));
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/BatchType.java

@@ -0,0 +1,5 @@
+package de.effigenix.domain.inventory;
+
+public enum BatchType {
+    PRODUCED, PURCHASED
+}

backend/src/main/java/de/effigenix/domain/inventory/Stock.java

@@ -3,6 +3,9 @@ package de.effigenix.domain.inventory;
 import de.effigenix.domain.masterdata.ArticleId;
 import de.effigenix.shared.common.Result;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -12,6 +15,7 @@ import java.util.Objects;
  * - ArticleId + StorageLocationId = unique (Application Layer, Repository-Concern)
  * - MinimumLevel optional (quantity amount >= 0)
  * - MinimumShelfLife optional (days > 0)
+ * - BatchReference (batchId + batchType) unique within batches
  */
 public class Stock {
 
@@ -20,19 +24,22 @@ public class Stock {
     private final StorageLocationId storageLocationId;
     private MinimumLevel minimumLevel;
     private MinimumShelfLife minimumShelfLife;
+    private final List<StockBatch> batches;
 
     private Stock(
             StockId id,
             ArticleId articleId,
             StorageLocationId storageLocationId,
             MinimumLevel minimumLevel,
-            MinimumShelfLife minimumShelfLife
+            MinimumShelfLife minimumShelfLife,
+            List<StockBatch> batches
     ) {
         this.id = id;
         this.articleId = articleId;
         this.storageLocationId = storageLocationId;
         this.minimumLevel = minimumLevel;
         this.minimumShelfLife = minimumShelfLife;
+        this.batches = new ArrayList<>(batches);
     }
 
     /**
@@ -81,7 +88,7 @@ public class Stock {
         }
 
         return Result.success(new Stock(
-                StockId.generate(), articleId, storageLocationId, minimumLevel, minimumShelfLife
+                StockId.generate(), articleId, storageLocationId, minimumLevel, minimumShelfLife, List.of()
         ));
     }
 
@@ -93,9 +100,28 @@ public class Stock {
             ArticleId articleId,
             StorageLocationId storageLocationId,
             MinimumLevel minimumLevel,
-            MinimumShelfLife minimumShelfLife
+            MinimumShelfLife minimumShelfLife,
+            List<StockBatch> batches
     ) {
-        return new Stock(id, articleId, storageLocationId, minimumLevel, minimumShelfLife);
+        return new Stock(id, articleId, storageLocationId, minimumLevel, minimumShelfLife, batches);
+    }
+
+    // ==================== Batch Management ====================
+
+    public Result<StockError, StockBatch> addBatch(StockBatchDraft draft) {
+        StockBatch batch;
+        switch (StockBatch.create(draft)) {
+            case Result.Failure(var err) -> { return Result.failure(err); }
+            case Result.Success(var val) -> batch = val;
+        }
+
+        if (hasBatchReference(batch.batchReference())) {
+            return Result.failure(new StockError.DuplicateBatchReference(
+                    batch.batchReference().batchId(), batch.batchReference().batchType().name()));
+        }
+
+        this.batches.add(batch);
+        return Result.success(batch);
     }
 
     // ==================== Getters ====================
@@ -105,6 +131,13 @@ public class Stock {
     public StorageLocationId storageLocationId() { return storageLocationId; }
     public MinimumLevel minimumLevel() { return minimumLevel; }
     public MinimumShelfLife minimumShelfLife() { return minimumShelfLife; }
+    public List<StockBatch> batches() { return Collections.unmodifiableList(batches); }
+
+    // ==================== Helpers ====================
+
+    private boolean hasBatchReference(BatchReference ref) {
+        return batches.stream().anyMatch(b -> b.batchReference().equals(ref));
+    }
 
     @Override
     public boolean equals(Object obj) {

backend/src/main/java/de/effigenix/domain/inventory/StockBatch.java

@@ -0,0 +1,115 @@
+package de.effigenix.domain.inventory;
+
+import de.effigenix.shared.common.Quantity;
+import de.effigenix.shared.common.Result;
+import de.effigenix.shared.common.UnitOfMeasure;
+
+import java.math.BigDecimal;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.format.DateTimeParseException;
+import java.util.Objects;
+
+/**
+ * Child entity of Stock representing a single batch (Charge).
+ *
+ * Invariants:
+ * - BatchReference (batchId + batchType) must be valid
+ * - Quantity must be positive
+ * - ExpiryDate must be a valid ISO date
+ * - New batches always have status AVAILABLE
+ * - receivedAt is set automatically on creation
+ */
+public class StockBatch {
+
+    private final StockBatchId id;
+    private final BatchReference batchReference;
+    private final Quantity quantity;
+    private final LocalDate expiryDate;
+    private final StockBatchStatus status;
+    private final Instant receivedAt;
+
+    private StockBatch(StockBatchId id, BatchReference batchReference, Quantity quantity,
+                       LocalDate expiryDate, StockBatchStatus status, Instant receivedAt) {
+        this.id = id;
+        this.batchReference = batchReference;
+        this.quantity = quantity;
+        this.expiryDate = expiryDate;
+        this.status = status;
+        this.receivedAt = receivedAt;
+    }
+
+    public static Result<StockError, StockBatch> create(StockBatchDraft draft) {
+        // 1. BatchReference validieren
+        BatchReference batchReference;
+        switch (BatchReference.of(draft.batchId(), draft.batchType())) {
+            case Result.Failure(var err) -> { return Result.failure(err); }
+            case Result.Success(var val) -> batchReference = val;
+        }
+
+        // 2. Quantity validieren (Pflicht, positiv)
+        Quantity quantity;
+        try {
+            BigDecimal amount = new BigDecimal(draft.quantityAmount());
+            UnitOfMeasure uom;
+            try {
+                uom = UnitOfMeasure.valueOf(draft.quantityUnit());
+            } catch (IllegalArgumentException | NullPointerException e) {
+                return Result.failure(new StockError.InvalidQuantity("Invalid unit: " + draft.quantityUnit()));
+            }
+            switch (Quantity.of(amount, uom)) {
+                case Result.Failure(var err) -> {
+                    return Result.failure(new StockError.InvalidQuantity(err.message()));
+                }
+                case Result.Success(var val) -> quantity = val;
+            }
+        } catch (NumberFormatException | NullPointerException e) {
+            return Result.failure(new StockError.InvalidQuantity(
+                    "Invalid quantity amount: " + draft.quantityAmount()));
+        }
+
+        // 3. ExpiryDate validieren (Pflicht)
+        LocalDate expiryDate;
+        try {
+            if (draft.expiryDate() == null || draft.expiryDate().isBlank()) {
+                return Result.failure(new StockError.InvalidExpiryDate("expiryDate must not be blank"));
+            }
+            expiryDate = LocalDate.parse(draft.expiryDate());
+        } catch (DateTimeParseException e) {
+            return Result.failure(new StockError.InvalidExpiryDate(
+                    "Invalid ISO date: " + draft.expiryDate()));
+        }
+
+        return Result.success(new StockBatch(
+                StockBatchId.generate(), batchReference, quantity,
+                expiryDate, StockBatchStatus.AVAILABLE, Instant.now()
+        ));
+    }
+
+    public static StockBatch reconstitute(StockBatchId id, BatchReference batchReference,
+                                           Quantity quantity, LocalDate expiryDate,
+                                           StockBatchStatus status, Instant receivedAt) {
+        return new StockBatch(id, batchReference, quantity, expiryDate, status, receivedAt);
+    }
+
+    // ==================== Getters ====================
+
+    public StockBatchId id() { return id; }
+    public BatchReference batchReference() { return batchReference; }
+    public Quantity quantity() { return quantity; }
+    public LocalDate expiryDate() { return expiryDate; }
+    public StockBatchStatus status() { return status; }
+    public Instant receivedAt() { return receivedAt; }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof StockBatch other)) return false;
+        return Objects.equals(id, other.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/StockBatchDraft.java

@@ -0,0 +1,9 @@
+package de.effigenix.domain.inventory;
+
+public record StockBatchDraft(
+        String batchId,
+        String batchType,
+        String quantityAmount,
+        String quantityUnit,
+        String expiryDate
+) {}

backend/src/main/java/de/effigenix/domain/inventory/StockBatchId.java

@@ -0,0 +1,20 @@
+package de.effigenix.domain.inventory;
+
+import java.util.UUID;
+
+public record StockBatchId(String value) {
+
+    public StockBatchId {
+        if (value == null || value.isBlank()) {
+            throw new IllegalArgumentException("StockBatchId must not be blank");
+        }
+    }
+
+    public static StockBatchId generate() {
+        return new StockBatchId(UUID.randomUUID().toString());
+    }
+
+    public static StockBatchId of(String value) {
+        return new StockBatchId(value);
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/StockBatchStatus.java

@@ -0,0 +1,5 @@
+package de.effigenix.domain.inventory;
+
+public enum StockBatchStatus {
+    AVAILABLE, EXPIRING_SOON, BLOCKED, EXPIRED
+}

backend/src/main/java/de/effigenix/domain/inventory/StockError.java

@@ -35,6 +35,31 @@ public sealed interface StockError {
         @Override public String message() { return "Invalid storage location ID: " + reason; }
     }
 
+    record InvalidBatchReference(String reason) implements StockError {
+        @Override public String code() { return "INVALID_BATCH_REFERENCE"; }
+        @Override public String message() { return "Invalid batch reference: " + reason; }
+    }
+
+    record DuplicateBatchReference(String batchId, String batchType) implements StockError {
+        @Override public String code() { return "DUPLICATE_BATCH_REFERENCE"; }
+        @Override public String message() { return "Batch reference already exists: " + batchId + "/" + batchType; }
+    }
+
+    record InvalidQuantity(String reason) implements StockError {
+        @Override public String code() { return "INVALID_QUANTITY"; }
+        @Override public String message() { return "Invalid quantity: " + reason; }
+    }
+
+    record InvalidExpiryDate(String reason) implements StockError {
+        @Override public String code() { return "INVALID_EXPIRY_DATE"; }
+        @Override public String message() { return "Invalid expiry date: " + reason; }
+    }
+
+    record BatchNotFound(String id) implements StockError {
+        @Override public String code() { return "BATCH_NOT_FOUND"; }
+        @Override public String message() { return "Batch not found: " + id; }
+    }
+
     record Unauthorized(String message) implements StockError {
         @Override public String code() { return "UNAUTHORIZED"; }
     }

backend/src/main/java/de/effigenix/infrastructure/config/InventoryUseCaseConfiguration.java

@@ -1,6 +1,7 @@
 package de.effigenix.infrastructure.config;
 
 import de.effigenix.application.inventory.ActivateStorageLocation;
+import de.effigenix.application.inventory.AddStockBatch;
 import de.effigenix.application.inventory.CreateStock;
 import de.effigenix.application.inventory.CreateStorageLocation;
 import de.effigenix.application.inventory.DeactivateStorageLocation;
@@ -47,4 +48,9 @@ public class InventoryUseCaseConfiguration {
     public CreateStock createStock(StockRepository stockRepository) {
         return new CreateStock(stockRepository);
     }
+
+    @Bean
+    public AddStockBatch addStockBatch(StockRepository stockRepository) {
+        return new AddStockBatch(stockRepository);
+    }
 }

backend/src/main/java/de/effigenix/infrastructure/inventory/persistence/entity/StockBatchEntity.java

@@ -0,0 +1,77 @@
+package de.effigenix.infrastructure.inventory.persistence.entity;
+
+import jakarta.persistence.*;
+
+import java.math.BigDecimal;
+import java.time.Instant;
+import java.time.LocalDate;
+
+@Entity
+@Table(name = "stock_batches")
+public class StockBatchEntity {
+
+    @Id
+    @Column(name = "id", nullable = false, length = 36)
+    private String id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "stock_id", nullable = false)
+    private StockEntity stock;
+
+    @Column(name = "batch_id", nullable = false, length = 100)
+    private String batchId;
+
+    @Column(name = "batch_type", nullable = false, length = 20)
+    private String batchType;
+
+    @Column(name = "quantity_amount", nullable = false, precision = 19, scale = 6)
+    private BigDecimal quantityAmount;
+
+    @Column(name = "quantity_unit", nullable = false, length = 20)
+    private String quantityUnit;
+
+    @Column(name = "expiry_date", nullable = false)
+    private LocalDate expiryDate;
+
+    @Column(name = "status", nullable = false, length = 20)
+    private String status;
+
+    @Column(name = "received_at", nullable = false)
+    private Instant receivedAt;
+
+    protected StockBatchEntity() {}
+
+    public StockBatchEntity(String id, StockEntity stock, String batchId, String batchType,
+                            BigDecimal quantityAmount, String quantityUnit, LocalDate expiryDate,
+                            String status, Instant receivedAt) {
+        this.id = id;
+        this.stock = stock;
+        this.batchId = batchId;
+        this.batchType = batchType;
+        this.quantityAmount = quantityAmount;
+        this.quantityUnit = quantityUnit;
+        this.expiryDate = expiryDate;
+        this.status = status;
+        this.receivedAt = receivedAt;
+    }
+
+    public String getId() { return id; }
+    public StockEntity getStock() { return stock; }
+    public String getBatchId() { return batchId; }
+    public String getBatchType() { return batchType; }
+    public BigDecimal getQuantityAmount() { return quantityAmount; }
+    public String getQuantityUnit() { return quantityUnit; }
+    public LocalDate getExpiryDate() { return expiryDate; }
+    public String getStatus() { return status; }
+    public Instant getReceivedAt() { return receivedAt; }
+
+    public void setId(String id) { this.id = id; }
+    public void setStock(StockEntity stock) { this.stock = stock; }
+    public void setBatchId(String batchId) { this.batchId = batchId; }
+    public void setBatchType(String batchType) { this.batchType = batchType; }
+    public void setQuantityAmount(BigDecimal quantityAmount) { this.quantityAmount = quantityAmount; }
+    public void setQuantityUnit(String quantityUnit) { this.quantityUnit = quantityUnit; }
+    public void setExpiryDate(LocalDate expiryDate) { this.expiryDate = expiryDate; }
+    public void setStatus(String status) { this.status = status; }
+    public void setReceivedAt(Instant receivedAt) { this.receivedAt = receivedAt; }
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/persistence/entity/StockEntity.java

@@ -3,6 +3,8 @@ package de.effigenix.infrastructure.inventory.persistence.entity;
 import jakarta.persistence.*;
 
 import java.math.BigDecimal;
+import java.util.ArrayList;
+import java.util.List;
 
 @Entity
 @Table(name = "stocks")
@@ -27,6 +29,9 @@ public class StockEntity {
     @Column(name = "minimum_shelf_life_days")
     private Integer minimumShelfLifeDays;
 
+    @OneToMany(mappedBy = "stock", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.EAGER)
+    private List<StockBatchEntity> batches = new ArrayList<>();
+
     public StockEntity() {}
 
     // ==================== Getters & Setters ====================
@@ -48,4 +53,7 @@ public class StockEntity {
 
     public Integer getMinimumShelfLifeDays() { return minimumShelfLifeDays; }
     public void setMinimumShelfLifeDays(Integer minimumShelfLifeDays) { this.minimumShelfLifeDays = minimumShelfLifeDays; }
+
+    public List<StockBatchEntity> getBatches() { return batches; }
+    public void setBatches(List<StockBatchEntity> batches) { this.batches = batches; }
 }

backend/src/main/java/de/effigenix/infrastructure/inventory/persistence/mapper/StockMapper.java

@@ -4,9 +4,13 @@ import de.effigenix.domain.inventory.*;
 import de.effigenix.domain.masterdata.ArticleId;
 import de.effigenix.shared.common.Quantity;
 import de.effigenix.shared.common.UnitOfMeasure;
+import de.effigenix.infrastructure.inventory.persistence.entity.StockBatchEntity;
 import de.effigenix.infrastructure.inventory.persistence.entity.StockEntity;
 import org.springframework.stereotype.Component;
 
+import java.util.List;
+import java.util.stream.Collectors;
+
 @Component
 public class StockMapper {
 
@@ -25,6 +29,11 @@ public class StockMapper {
             entity.setMinimumShelfLifeDays(stock.minimumShelfLife().days());
         }
 
+        List<StockBatchEntity> batchEntities = stock.batches().stream()
+                .map(b -> toBatchEntity(b, entity))
+                .collect(Collectors.toList());
+        entity.setBatches(batchEntities);
+
         return entity;
     }
 
@@ -44,12 +53,46 @@ public class StockMapper {
             minimumShelfLife = new MinimumShelfLife(entity.getMinimumShelfLifeDays());
         }
 
+        List<StockBatch> batches = entity.getBatches().stream()
+                .map(this::toDomainBatch)
+                .collect(Collectors.toList());
+
         return Stock.reconstitute(
                 StockId.of(entity.getId()),
                 ArticleId.of(entity.getArticleId()),
                 StorageLocationId.of(entity.getStorageLocationId()),
                 minimumLevel,
-                minimumShelfLife
+                minimumShelfLife,
+                batches
+        );
+    }
+
+    private StockBatchEntity toBatchEntity(StockBatch batch, StockEntity stockEntity) {
+        return new StockBatchEntity(
+                batch.id().value(),
+                stockEntity,
+                batch.batchReference().batchId(),
+                batch.batchReference().batchType().name(),
+                batch.quantity().amount(),
+                batch.quantity().uom().name(),
+                batch.expiryDate(),
+                batch.status().name(),
+                batch.receivedAt()
+        );
+    }
+
+    private StockBatch toDomainBatch(StockBatchEntity entity) {
+        return StockBatch.reconstitute(
+                StockBatchId.of(entity.getId()),
+                new BatchReference(entity.getBatchId(), BatchType.valueOf(entity.getBatchType())),
+                Quantity.reconstitute(
+                        entity.getQuantityAmount(),
+                        UnitOfMeasure.valueOf(entity.getQuantityUnit()),
+                        null, null
+                ),
+                entity.getExpiryDate(),
+                StockBatchStatus.valueOf(entity.getStatus()),
+                entity.getReceivedAt()
         );
     }
 }

backend/src/main/java/de/effigenix/infrastructure/inventory/web/controller/StockController.java

@@ -1,9 +1,13 @@
 package de.effigenix.infrastructure.inventory.web.controller;
 
+import de.effigenix.application.inventory.AddStockBatch;
 import de.effigenix.application.inventory.CreateStock;
+import de.effigenix.application.inventory.command.AddStockBatchCommand;
 import de.effigenix.application.inventory.command.CreateStockCommand;
 import de.effigenix.domain.inventory.StockError;
+import de.effigenix.infrastructure.inventory.web.dto.AddStockBatchRequest;
 import de.effigenix.infrastructure.inventory.web.dto.CreateStockRequest;
+import de.effigenix.infrastructure.inventory.web.dto.StockBatchResponse;
 import de.effigenix.infrastructure.inventory.web.dto.StockResponse;
 import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
@@ -25,9 +29,11 @@ public class StockController {
     private static final Logger logger = LoggerFactory.getLogger(StockController.class);
 
     private final CreateStock createStock;
+    private final AddStockBatch addStockBatch;
 
-    public StockController(CreateStock createStock) {
+    public StockController(CreateStock createStock, AddStockBatch addStockBatch) {
         this.createStock = createStock;
+        this.addStockBatch = addStockBatch;
     }
 
     @PostMapping
@@ -55,6 +61,31 @@ public class StockController {
                 .body(StockResponse.from(result.unsafeGetValue()));
     }
 
+    @PostMapping("/{stockId}/batches")
+    @PreAuthorize("hasAuthority('STOCK_WRITE')")
+    public ResponseEntity<StockBatchResponse> addBatch(
+            @PathVariable String stockId,
+            @Valid @RequestBody AddStockBatchRequest request,
+            Authentication authentication
+    ) {
+        logger.info("Adding batch to stock: {} by actor: {}", stockId, authentication.getName());
+
+        var cmd = new AddStockBatchCommand(
+                stockId, request.batchId(), request.batchType(),
+                request.quantityAmount(), request.quantityUnit(),
+                request.expiryDate()
+        );
+        var result = addStockBatch.execute(cmd);
+
+        if (result.isFailure()) {
+            throw new StockDomainErrorException(result.unsafeGetError());
+        }
+
+        logger.info("Batch added: {}", result.unsafeGetValue().id().value());
+        return ResponseEntity.status(HttpStatus.CREATED)
+                .body(StockBatchResponse.from(result.unsafeGetValue()));
+    }
+
     public static class StockDomainErrorException extends RuntimeException {
         private final StockError error;
 

backend/src/main/java/de/effigenix/infrastructure/inventory/web/dto/AddStockBatchRequest.java

@@ -0,0 +1,11 @@
+package de.effigenix.infrastructure.inventory.web.dto;
+
+import jakarta.validation.constraints.NotBlank;
+
+public record AddStockBatchRequest(
+        @NotBlank String batchId,
+        @NotBlank String batchType,
+        @NotBlank String quantityAmount,
+        @NotBlank String quantityUnit,
+        @NotBlank String expiryDate
+) {}

backend/src/main/java/de/effigenix/infrastructure/inventory/web/dto/StockBatchResponse.java

@@ -0,0 +1,32 @@
+package de.effigenix.infrastructure.inventory.web.dto;
+
+import de.effigenix.domain.inventory.StockBatch;
+
+import java.math.BigDecimal;
+import java.time.Instant;
+import java.time.LocalDate;
+
+public record StockBatchResponse(
+        String id,
+        String batchId,
+        String batchType,
+        BigDecimal quantityAmount,
+        String quantityUnit,
+        LocalDate expiryDate,
+        String status,
+        Instant receivedAt
+) {
+
+    public static StockBatchResponse from(StockBatch batch) {
+        return new StockBatchResponse(
+                batch.id().value(),
+                batch.batchReference().batchId(),
+                batch.batchReference().batchType().name(),
+                batch.quantity().amount(),
+                batch.quantity().uom().name(),
+                batch.expiryDate(),
+                batch.status().name(),
+                batch.receivedAt()
+        );
+    }
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/web/exception/InventoryErrorHttpStatusMapper.java

@@ -25,11 +25,16 @@ public final class InventoryErrorHttpStatusMapper {
     public static int toHttpStatus(StockError error) {
         return switch (error) {
             case StockError.StockNotFound e -> 404;
+            case StockError.BatchNotFound e -> 404;
             case StockError.DuplicateStock e -> 409;
+            case StockError.DuplicateBatchReference e -> 409;
             case StockError.InvalidMinimumLevel e -> 400;
             case StockError.InvalidMinimumShelfLife e -> 400;
             case StockError.InvalidArticleId e -> 400;
             case StockError.InvalidStorageLocationId e -> 400;
+            case StockError.InvalidBatchReference e -> 400;
+            case StockError.InvalidQuantity e -> 400;
+            case StockError.InvalidExpiryDate e -> 400;
             case StockError.Unauthorized e -> 403;
             case StockError.RepositoryFailure e -> 500;
         };

backend/src/main/java/de/effigenix/infrastructure/stub/StubStockRepository.java

@@ -0,0 +1,41 @@
+package de.effigenix.infrastructure.stub;
+
+import de.effigenix.domain.inventory.Stock;
+import de.effigenix.domain.inventory.StockId;
+import de.effigenix.domain.inventory.StockRepository;
+import de.effigenix.domain.inventory.StorageLocationId;
+import de.effigenix.domain.masterdata.ArticleId;
+import de.effigenix.shared.common.RepositoryError;
+import de.effigenix.shared.common.Result;
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Repository;
+
+import java.util.Optional;
+
+@Repository
+@Profile("no-db")
+public class StubStockRepository implements StockRepository {
+
+    private static final RepositoryError.DatabaseError STUB_ERROR =
+            new RepositoryError.DatabaseError("Stub-Modus: keine Datenbankverbindung");
+
+    @Override
+    public Result<RepositoryError, Optional<Stock>> findById(StockId id) {
+        return Result.failure(STUB_ERROR);
+    }
+
+    @Override
+    public Result<RepositoryError, Optional<Stock>> findByArticleIdAndStorageLocationId(ArticleId articleId, StorageLocationId storageLocationId) {
+        return Result.failure(STUB_ERROR);
+    }
+
+    @Override
+    public Result<RepositoryError, Boolean> existsByArticleIdAndStorageLocationId(ArticleId articleId, StorageLocationId storageLocationId) {
+        return Result.failure(STUB_ERROR);
+    }
+
+    @Override
+    public Result<RepositoryError, Void> save(Stock stock) {
+        return Result.failure(STUB_ERROR);
+    }
+}

backend/src/main/resources/db/changelog/changes/014-create-stock-batches-table.xml

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<databaseChangeLog
+        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
+        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
+
+    <changeSet id="014-create-stock-batches-table" author="effigenix">
+        <createTable tableName="stock_batches">
+            <column name="id" type="VARCHAR(36)">
+                <constraints primaryKey="true" nullable="false"/>
+            </column>
+            <column name="stock_id" type="VARCHAR(36)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="batch_id" type="VARCHAR(100)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="batch_type" type="VARCHAR(20)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="quantity_amount" type="DECIMAL(19,6)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="quantity_unit" type="VARCHAR(20)">
+                <constraints nullable="false"/>
+            </column>
+            <column name="expiry_date" type="DATE">
+                <constraints nullable="false"/>
+            </column>
+            <column name="status" type="VARCHAR(20)" defaultValue="AVAILABLE">
+                <constraints nullable="false"/>
+            </column>
+            <column name="received_at" type="TIMESTAMP WITH TIME ZONE">
+                <constraints nullable="false"/>
+            </column>
+        </createTable>
+
+        <addForeignKeyConstraint baseTableName="stock_batches" baseColumnNames="stock_id"
+                                 referencedTableName="stocks" referencedColumnNames="id"
+                                 constraintName="fk_stock_batches_stock"
+                                 onDelete="CASCADE"/>
+
+        <addUniqueConstraint tableName="stock_batches" columnNames="stock_id, batch_id, batch_type"
+                             constraintName="uq_stock_batch_reference"/>
+
+        <createIndex tableName="stock_batches" indexName="idx_stock_batches_stock_id">
+            <column name="stock_id"/>
+        </createIndex>
+
+        <sql>
+            ALTER TABLE stock_batches ADD CONSTRAINT chk_stock_batch_type
+                CHECK (batch_type IN ('PRODUCED', 'PURCHASED'));
+        </sql>
+
+        <sql>
+            ALTER TABLE stock_batches ADD CONSTRAINT chk_stock_batch_status
+                CHECK (status IN ('AVAILABLE', 'EXPIRING_SOON', 'BLOCKED', 'EXPIRED'));
+        </sql>
+    </changeSet>
+
+</databaseChangeLog>

backend/src/main/resources/db/changelog/db.changelog-master.xml

@@ -18,5 +18,6 @@
     <include file="db/changelog/changes/011-create-recipe-ingredients-table.xml"/>
     <include file="db/changelog/changes/012-create-recipe-production-steps-table.xml"/>
     <include file="db/changelog/changes/013-create-stock-schema.xml"/>
+    <include file="db/changelog/changes/014-create-stock-batches-table.xml"/>
 
 </databaseChangeLog>