From 1656739ecde2b71eda920dd95dfb6c8c6aeac393 Mon Sep 17 00:00:00 2001
From: kusowl <kushal.saha@outlook.com>
Date: Mon, 9 Mar 2026 19:07:27 +0530
Subject: [PATCH 1/2] feature: add and fetch products in cart api

- schema for cart and product
- define relationship, DTO, Resource and API collections
- Add post and get endpoint for cart api
---
 .../app/Actions/AddProductToCartAction.php    | 46 +++++++++++++++++
 .../app/Actions/GetActiveUserCartAction.php   | 17 +++++++
 backend/app/Data/AddToCartDTO.php             | 33 ++++++++++++
 backend/app/Data/CartDTO.php                  | 49 ++++++++++++++++++
 backend/app/Data/CartItemDTO.php              | 32 ++++++++++++
 backend/app/Enums/CartStatus.php              | 11 ++++
 .../app/Http/Controllers/CartController.php   | 51 +++++++++++++++++++
 .../Http/Requests/AddProductToCartRequest.php | 29 +++++++++++
 .../app/Http/Resources/CartItemCollection.php | 19 +++++++
 .../app/Http/Resources/CartItemResource.php   | 31 +++++++++++
 backend/app/Http/Resources/CartResource.php   | 30 +++++++++++
 backend/app/Models/Cart.php                   | 46 +++++++++++++++++
 backend/app/Models/Product.php                |  5 ++
 backend/app/Models/User.php                   |  5 ++
 .../2026_03_06_054113_create_carts_table.php  | 31 +++++++++++
 .../2026_03_06_055910_cart_product.php        | 35 +++++++++++++
 backend/routes/api.php                        |  4 ++
 17 files changed, 474 insertions(+)
 create mode 100644 backend/app/Actions/AddProductToCartAction.php
 create mode 100644 backend/app/Actions/GetActiveUserCartAction.php
 create mode 100644 backend/app/Data/AddToCartDTO.php
 create mode 100644 backend/app/Data/CartDTO.php
 create mode 100644 backend/app/Data/CartItemDTO.php
 create mode 100644 backend/app/Enums/CartStatus.php
 create mode 100644 backend/app/Http/Controllers/CartController.php
 create mode 100644 backend/app/Http/Requests/AddProductToCartRequest.php
 create mode 100644 backend/app/Http/Resources/CartItemCollection.php
 create mode 100644 backend/app/Http/Resources/CartItemResource.php
 create mode 100644 backend/app/Http/Resources/CartResource.php
 create mode 100644 backend/app/Models/Cart.php
 create mode 100644 backend/database/migrations/2026_03_06_054113_create_carts_table.php
 create mode 100644 backend/database/migrations/2026_03_06_055910_cart_product.php

diff --git a/backend/app/Actions/AddProductToCartAction.php b/backend/app/Actions/AddProductToCartAction.php
new file mode 100644
index 0000000..99aac55
--- /dev/null
+++ b/backend/app/Actions/AddProductToCartAction.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Actions;
+
+use App\Data\AddToCartDTO;
+use App\Data\CartDTO;
+use App\Enums\CartStatus;
+use App\Models\Product;
+use App\Models\User;
+
+final readonly class AddProductToCartAction
+{
+    /**
+     * Execute the action.
+     */
+    public function execute(AddToCartDTO $cartData, User $user)
+    {
+        $cart = $user->carts()->active()->firstOrCreate([
+            'status' => CartStatus::Active,
+        ]);
+
+        $price = Product::query()->whereId($cartData->productId)->value('actual_price');
+
+        $productInCart = $cart->products()->find($cartData->productId);
+
+        if ($productInCart) {
+            $newQuantity = $productInCart->pivot->quantity + $cartData->quantity;
+
+            $cart->products()->updateExistingPivot($cartData->productId, [
+                'quantity' => $newQuantity,
+                'price' => $price,
+            ]);
+
+        } else {
+            $cart->products()->attach($cartData->productId, [
+                'quantity' => $cartData->quantity,
+                'price' => $price,
+            ]);
+        }
+
+        return CartDTO::fromModel($cart->load(['products' => function ($query) {
+            $query->withPivot('quantity', 'price');
+        }]));
+
+    }
+}
diff --git a/backend/app/Actions/GetActiveUserCartAction.php b/backend/app/Actions/GetActiveUserCartAction.php
new file mode 100644
index 0000000..9fd8a7b
--- /dev/null
+++ b/backend/app/Actions/GetActiveUserCartAction.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace App\Actions;
+
+use App\Data\CartDTO;
+use App\Models\User;
+
+final readonly class GetActiveUserCartAction
+{
+    /**
+     * Execute the action.
+     */
+    public function execute(User $user)
+    {
+        return CartDTO::fromModel($user->carts()->active()->withProducts()->first());
+    }
+}
diff --git a/backend/app/Data/AddToCartDTO.php b/backend/app/Data/AddToCartDTO.php
new file mode 100644
index 0000000..2035573
--- /dev/null
+++ b/backend/app/Data/AddToCartDTO.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Data;
+
+use App\Contracts\InputDataTransferObject;
+use Illuminate\Foundation\Http\FormRequest;
+
+final readonly class AddToCartDTO implements InputDataTransferObject
+{
+    public function __construct(
+        public int $productId,
+        public int $quantity
+    ) {}
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function toArray(): array
+    {
+        return [
+            'productId' => $this->productId,
+            'quantity' => $this->quantity,
+        ];
+    }
+
+    public static function fromRequest(FormRequest $request): InputDataTransferObject
+    {
+        return new self(
+            productId: $request->productId,
+            quantity: $request->quantity
+        );
+    }
+}
diff --git a/backend/app/Data/CartDTO.php b/backend/app/Data/CartDTO.php
new file mode 100644
index 0000000..f618ccd
--- /dev/null
+++ b/backend/app/Data/CartDTO.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace App\Data;
+
+use App\Contracts\OutputDataTransferObject;
+use App\Models\Cart;
+
+final readonly class CartDTO implements OutputDataTransferObject
+{
+    /**
+     * @param  CartItemDTO[]  $items
+     */
+    public function __construct(
+        public int $id,
+        public ?int $itemsCount = null,
+        public ?int $totalPrice = null,
+        public array $items = []
+    ) {}
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function toArray(): array
+    {
+        return [
+            'id' => $this->id,
+            'itemsCount' => $this->itemsCount,
+            'totalPrice' => $this->totalPrice,
+            'items' => $this->items,
+        ];
+    }
+
+    public static function fromModel(Cart $cart)
+    {
+        return new self(
+            id: $cart->id,
+            itemsCount: $cart->products->count(),
+            totalPrice: $cart->products->sum(fn ($product) => $product->pivot->price * $product->pivot->quantity),
+            items: $cart->products->map(fn ($product) => new CartItemDTO(
+                id: $product->id,
+                title: $product->title,
+                quantity: $product->pivot->quantity,
+                price: $product->actual_price,
+                subtotal: $product->actual_price * $product->pivot->quantity,
+                image: $product->images->first()->path,
+            ))->toArray()
+        );
+    }
+}
diff --git a/backend/app/Data/CartItemDTO.php b/backend/app/Data/CartItemDTO.php
new file mode 100644
index 0000000..8e024ff
--- /dev/null
+++ b/backend/app/Data/CartItemDTO.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace App\Data;
+
+use App\Contracts\OutputDataTransferObject;
+
+final readonly class CartItemDTO implements OutputDataTransferObject
+{
+    public function __construct(
+        public int $id,
+        public string $title,
+        public int $quantity,
+        public float $price,
+        public float $subtotal,
+        public string $image
+    ) {}
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function toArray(): array
+    {
+        return [
+            'id' => $this->id,
+            'title' => $this->title,
+            'quantity' => $this->quantity,
+            'price' => $this->price,
+            'subtotal' => $this->subtotal,
+            'image' => $this->image,
+        ];
+    }
+}
diff --git a/backend/app/Enums/CartStatus.php b/backend/app/Enums/CartStatus.php
new file mode 100644
index 0000000..c06b8cc
--- /dev/null
+++ b/backend/app/Enums/CartStatus.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace App\Enums;
+
+enum CartStatus: string
+{
+    case Active = 'active'; // freshly created
+    case Converted = 'converted'; // user ordered
+    case Abandoned = 'abandoned'; // older than 24hrs
+    case Expired = 'expired'; // left for a long period
+}
diff --git a/backend/app/Http/Controllers/CartController.php b/backend/app/Http/Controllers/CartController.php
new file mode 100644
index 0000000..f54bfee
--- /dev/null
+++ b/backend/app/Http/Controllers/CartController.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Actions\AddProductToCartAction;
+use App\Actions\GetActiveUserCartAction;
+use App\Data\AddToCartDTO;
+use App\Http\Requests\AddProductToCartRequest;
+use App\Http\Resources\CartResource;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Auth;
+
+class CartController extends Controller
+{
+    /**
+     * Store a newly created resource in storage.
+     */
+    public function store(AddProductToCartRequest $request, AddProductToCartAction $addProductAction)
+    {
+        $addToCartData = AddToCartDTO::fromRequest($request);
+
+        $cart = $addProductAction->execute($addToCartData, Auth::user());
+
+        return new CartResource($cart);
+
+    }
+
+    /**
+     * Display the specified resource.
+     */
+    public function show(GetActiveUserCartAction $action)
+    {
+        return new CartResource($action->execute(Auth::user()));
+    }
+
+    /**
+     * Update the specified resource in storage.
+     */
+    public function update(Request $request, string $id)
+    {
+        //
+    }
+
+    /**
+     * Remove the specified resource from storage.
+     */
+    public function destroy(string $id)
+    {
+        //
+    }
+}
diff --git a/backend/app/Http/Requests/AddProductToCartRequest.php b/backend/app/Http/Requests/AddProductToCartRequest.php
new file mode 100644
index 0000000..12615f5
--- /dev/null
+++ b/backend/app/Http/Requests/AddProductToCartRequest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class AddProductToCartRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     */
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array<string, \Illuminate\Contracts\Validation\ValidationRule|array<mixed>|string>
+     */
+    public function rules(): array
+    {
+        return [
+            'productId' => 'required|exists:products,id',
+            'quantity' => 'required|numeric|min:1',
+        ];
+    }
+}
diff --git a/backend/app/Http/Resources/CartItemCollection.php b/backend/app/Http/Resources/CartItemCollection.php
new file mode 100644
index 0000000..69073c5
--- /dev/null
+++ b/backend/app/Http/Resources/CartItemCollection.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Http\Resources;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\ResourceCollection;
+
+class CartItemCollection extends ResourceCollection
+{
+    /**
+     * Transform the resource collection into an array.
+     *
+     * @return array<int|string, mixed>
+     */
+    public function toArray(Request $request): array
+    {
+        return parent::toArray($request);
+    }
+}
diff --git a/backend/app/Http/Resources/CartItemResource.php b/backend/app/Http/Resources/CartItemResource.php
new file mode 100644
index 0000000..2510e20
--- /dev/null
+++ b/backend/app/Http/Resources/CartItemResource.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Http\Resources;
+
+use App\Data\CartItemDTO;
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+use Illuminate\Support\Facades\Storage;
+
+/**
+ * @property CartItemDTO $resource
+ */
+class CartItemResource extends JsonResource
+{
+    /**
+     * Transform the resource into an array.
+     *
+     * @return array<string, mixed>
+     */
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->resource->id,
+            'title' => $this->resource->title,
+            'quantity' => $this->resource->quantity,
+            'price' => $this->resource->price,
+            'subtotal' => $this->resource->subtotal,
+            'image' => Storage::disk('public')->url($this->resource->image),
+        ];
+    }
+}
diff --git a/backend/app/Http/Resources/CartResource.php b/backend/app/Http/Resources/CartResource.php
new file mode 100644
index 0000000..99ab883
--- /dev/null
+++ b/backend/app/Http/Resources/CartResource.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Http\Resources;
+
+use App\Data\CartDTO;
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+/**
+ * @property CartDTO $resource
+ */
+class CartResource extends JsonResource
+{
+    public static $wrap = null;
+
+    /**
+     * Transform the resource into an array.
+     *
+     * @return array<string, mixed>
+     */
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->resource->id,
+            'itemsCount' => $this->resource->itemsCount,
+            'totalPrice' => $this->resource->totalPrice,
+            'items' => CartItemResource::collection($this->resource->items),
+        ];
+    }
+}
diff --git a/backend/app/Models/Cart.php b/backend/app/Models/Cart.php
new file mode 100644
index 0000000..e50d6f2
--- /dev/null
+++ b/backend/app/Models/Cart.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Models;
+
+use App\Enums\CartStatus;
+use Illuminate\Database\Eloquent\Attributes\Scope;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Model;
+
+class Cart extends Model
+{
+    protected $fillable = ['user_id', 'status'];
+
+    protected function casts()
+    {
+        return [
+            'status' => CartStatus::class,
+        ];
+    }
+
+    public function products()
+    {
+        return $this->belongsToMany(Product::class)
+            ->withPivot('price', 'quantity')
+            ->withTimestamps();
+    }
+
+    public function user()
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    #[Scope]
+    protected function active(Builder $query)
+    {
+        return $query->where('status', CartStatus::Active);
+    }
+
+    #[Scope]
+    protected function withProducts(Builder $query)
+    {
+        return $query->with(['products' => function ($product) {
+            $product->withPivot('quantity', 'price');
+        }]);
+    }
+}
diff --git a/backend/app/Models/Product.php b/backend/app/Models/Product.php
index ef200b6..b6f84ab 100644
--- a/backend/app/Models/Product.php
+++ b/backend/app/Models/Product.php
@@ -36,6 +36,11 @@ public function favoritedBy(): BelongsToMany
         return $this->belongsToMany(User::class, 'favorite_products');
     }
 
+    public function carts()
+    {
+        return $this->belongsToMany(Cart::class);
+    }
+
     #[Scope]
     protected function active(Builder $query): Builder
     {
diff --git a/backend/app/Models/User.php b/backend/app/Models/User.php
index a0ab8b4..7c68aa5 100644
--- a/backend/app/Models/User.php
+++ b/backend/app/Models/User.php
@@ -62,4 +62,9 @@ public function hasFavorited(Product $product): bool
     {
         return $this->favoriteProducts()->where('product_id', $product->id)->exists();
     }
+
+    public function carts()
+    {
+        return $this->hasMany(Cart::class);
+    }
 }
diff --git a/backend/database/migrations/2026_03_06_054113_create_carts_table.php b/backend/database/migrations/2026_03_06_054113_create_carts_table.php
new file mode 100644
index 0000000..8e68e1a
--- /dev/null
+++ b/backend/database/migrations/2026_03_06_054113_create_carts_table.php
@@ -0,0 +1,31 @@
+<?php
+
+use App\Enums\CartStatus;
+use App\Models\User;
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('carts', function (Blueprint $table) {
+            $table->id();
+            $table->foreignIdFor(User::class);
+            $table->enum('status', array_column(CartStatus::cases(), 'value'));
+            $table->timestamps();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('carts');
+    }
+};
diff --git a/backend/database/migrations/2026_03_06_055910_cart_product.php b/backend/database/migrations/2026_03_06_055910_cart_product.php
new file mode 100644
index 0000000..2bf77d1
--- /dev/null
+++ b/backend/database/migrations/2026_03_06_055910_cart_product.php
@@ -0,0 +1,35 @@
+<?php
+
+use App\Models\Cart;
+use App\Models\Product;
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('cart_product', function (Blueprint $table) {
+            $table->id();
+            $table->foreignIdFor(Cart::class);
+            $table->foreignIdFor(Product::class);
+            $table->decimal('price', 10, 2);
+            $table->integer('quantity');
+            $table->timestamps();
+
+            $table->unique(['cart_id', 'product_id']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('cart_product');
+    }
+};
diff --git a/backend/routes/api.php b/backend/routes/api.php
index 311580f..5da74c3 100644
--- a/backend/routes/api.php
+++ b/backend/routes/api.php
@@ -1,6 +1,7 @@
 <?php
 
 use App\Http\Controllers\AuthenticatedUserController;
+use App\Http\Controllers\CartController;
 use App\Http\Controllers\FavouriteProductController;
 use App\Http\Controllers\ProductCategoryController;
 use App\Http\Controllers\ProductController;
@@ -19,6 +20,9 @@
 
     // Favorites
     Route::post('/products/{product}/favorite', [FavouriteProductController::class, 'toggle']);
+
+    Route::post('/cart', [CartController::class, 'store']);
+    Route::get('/cart', [CartController::class, 'show']);
 });
 Route::get('/categories', [ProductCategoryController::class, 'index']);
 Route::apiResource('products', ProductController::class);

From 5bbec0ee2b6a24365560f2971dc9fa0e97296094 Mon Sep 17 00:00:00 2001
From: kusowl <kushal.saha@outlook.com>
Date: Tue, 10 Mar 2026 19:01:52 +0530
Subject: [PATCH 2/2] feature: update quantity and remove product from cart

add endpoint for update quantity of products (min:1, max:10)
add endpoint for removing product from cart
---
 .../Actions/RemoveProductFromCartAction.php   | 21 ++++++++++
 .../app/Actions/UpdateProductInCartAction.php | 34 +++++++++++++++
 .../app/Http/Controllers/CartController.php   | 42 ++++++++++++++++---
 .../Requests/RemoveProductFromCartRequest.php | 28 +++++++++++++
 .../Requests/UpdateProductInCartRequest.php   | 29 +++++++++++++
 backend/routes/api.php                        |  5 ++-
 6 files changed, 152 insertions(+), 7 deletions(-)
 create mode 100644 backend/app/Actions/RemoveProductFromCartAction.php
 create mode 100644 backend/app/Actions/UpdateProductInCartAction.php
 create mode 100644 backend/app/Http/Requests/RemoveProductFromCartRequest.php
 create mode 100644 backend/app/Http/Requests/UpdateProductInCartRequest.php

diff --git a/backend/app/Actions/RemoveProductFromCartAction.php b/backend/app/Actions/RemoveProductFromCartAction.php
new file mode 100644
index 0000000..b9ddceb
--- /dev/null
+++ b/backend/app/Actions/RemoveProductFromCartAction.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace App\Actions;
+
+use App\Models\User;
+
+final readonly class RemoveProductFromCartAction
+{
+    public function __construct(private GetActiveUserCartAction $activeCartAction) {}
+
+    /**
+     * Execute the action.
+     */
+    public function execute(int $productId, User $user)
+    {
+        $cart = $user->carts()->active()->sole();
+        $cart->products()->detach($productId);
+
+        return $this->activeCartAction->execute($user);
+    }
+}
diff --git a/backend/app/Actions/UpdateProductInCartAction.php b/backend/app/Actions/UpdateProductInCartAction.php
new file mode 100644
index 0000000..9bb4d8f
--- /dev/null
+++ b/backend/app/Actions/UpdateProductInCartAction.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace App\Actions;
+
+use App\Data\AddToCartDTO;
+use App\Data\CartDTO;
+use App\Models\User;
+use InvalidArgumentException;
+
+final readonly class UpdateProductInCartAction
+{
+    /**
+     * Execute the action.
+     *
+     * @throws InvalidArgumentException
+     */
+    public function execute(AddToCartDTO $cartData, User $user)
+    {
+        $cart = $user->carts()->active()->sole();
+
+        $productInCart = $cart->products()->find($cartData->productId);
+
+        throw_if($productInCart === null, new InvalidArgumentException('Product not found'));
+
+        $cart->products()->updateExistingPivot($cartData->productId, [
+            'quantity' => $cartData->quantity,
+        ]);
+
+        return CartDTO::fromModel($cart->load(['products' => function ($query) {
+            $query->withPivot('quantity', 'price');
+        }]));
+
+    }
+}
diff --git a/backend/app/Http/Controllers/CartController.php b/backend/app/Http/Controllers/CartController.php
index f54bfee..ffddc15 100644
--- a/backend/app/Http/Controllers/CartController.php
+++ b/backend/app/Http/Controllers/CartController.php
@@ -4,10 +4,13 @@
 
 use App\Actions\AddProductToCartAction;
 use App\Actions\GetActiveUserCartAction;
+use App\Actions\RemoveProductFromCartAction;
+use App\Actions\UpdateProductInCartAction;
 use App\Data\AddToCartDTO;
 use App\Http\Requests\AddProductToCartRequest;
+use App\Http\Requests\RemoveProductFromCartRequest;
+use App\Http\Requests\UpdateProductInCartRequest;
 use App\Http\Resources\CartResource;
-use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Auth;
 
 class CartController extends Controller
@@ -36,16 +39,45 @@ public function show(GetActiveUserCartAction $action)
     /**
      * Update the specified resource in storage.
      */
-    public function update(Request $request, string $id)
+    public function update(UpdateProductInCartRequest $request, UpdateProductInCartAction $action)
     {
-        //
+        $updateCartData = AddToCartDTO::fromRequest($request);
+        $cart = $action->execute($updateCartData, $request->user());
+
+        return new CartResource($cart);
     }
 
     /**
      * Remove the specified resource from storage.
      */
-    public function destroy(string $id)
+    public function destroy(RemoveProductFromCartRequest $request, RemoveProductFromCartAction $action)
     {
-        //
+        $user = $request->user();
+        try {
+            $cart = $action->execute($request->productId, $user);
+
+            return new CartResource($cart);
+        } catch (ModelNotFoundException $e) {
+
+            Log::error('No active cart found when removing a product from cart.', [
+                'user' => $user->id,
+                'error' => $e->getMessage(),
+            ]);
+
+            return response()->json([
+                'message' => 'No active cart found.',
+            ], 404);
+
+        } catch (MultipleRecordsFoundException $e) {
+            Log::error('Multiple active carts found for the user', [
+                'user' => $user->id,
+                'error' => $e->getMessage(),
+            ]);
+
+            return response()->json([
+                'message' => 'Multiple Active carts found.',
+            ], 409);
+        }
+
     }
 }
diff --git a/backend/app/Http/Requests/RemoveProductFromCartRequest.php b/backend/app/Http/Requests/RemoveProductFromCartRequest.php
new file mode 100644
index 0000000..d388f6d
--- /dev/null
+++ b/backend/app/Http/Requests/RemoveProductFromCartRequest.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class RemoveProductFromCartRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     */
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array<string, \Illuminate\Contracts\Validation\ValidationRule|array<mixed>|string>
+     */
+    public function rules(): array
+    {
+        return [
+            'productId' => ['required', 'exists:products,id'],
+        ];
+    }
+}
diff --git a/backend/app/Http/Requests/UpdateProductInCartRequest.php b/backend/app/Http/Requests/UpdateProductInCartRequest.php
new file mode 100644
index 0000000..adbc4d9
--- /dev/null
+++ b/backend/app/Http/Requests/UpdateProductInCartRequest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class UpdateProductInCartRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     */
+    public function authorize(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array<string, \Illuminate\Contracts\Validation\ValidationRule|array<mixed>|string>
+     */
+    public function rules(): array
+    {
+        return [
+            'productId' => ['required', 'exists:products,id'],
+            'quantity' => ['required', 'min:0', 'max:10'],
+        ];
+    }
+}
diff --git a/backend/routes/api.php b/backend/routes/api.php
index 5da74c3..c1dc546 100644
--- a/backend/routes/api.php
+++ b/backend/routes/api.php
@@ -21,8 +21,9 @@
     // Favorites
     Route::post('/products/{product}/favorite', [FavouriteProductController::class, 'toggle']);
 
-    Route::post('/cart', [CartController::class, 'store']);
-    Route::get('/cart', [CartController::class, 'show']);
+    Route::apiSingleton('/cart', CartController::class)
+        ->creatable()
+        ->destroyable();
 });
 Route::get('/categories', [ProductCategoryController::class, 'index']);
 Route::apiResource('products', ProductController::class);