diff --git a/prisma/migrations/0006_cart/migration.sql b/prisma/migrations/0006_cart/migration.sql
new file mode 100644
index 0000000..016aae5
--- /dev/null
+++ b/prisma/migrations/0006_cart/migration.sql
@@ -0,0 +1,34 @@
+CREATE TABLE "Cart" (
+    "id" TEXT NOT NULL,
+    "userId" TEXT NOT NULL,
+    "deliveryAddressId" TEXT,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "Cart_pkey" PRIMARY KEY ("id")
+);
+
+CREATE TABLE "CartItem" (
+    "id" TEXT NOT NULL,
+    "cartId" TEXT NOT NULL,
+    "productId" TEXT NOT NULL,
+    "productName" TEXT NOT NULL,
+    "sku" TEXT NOT NULL,
+    "isCustomizable" BOOLEAN NOT NULL DEFAULT false,
+    "quantity" DECIMAL(14,3) NOT NULL,
+    "parameters" JSONB NOT NULL,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "CartItem_pkey" PRIMARY KEY ("id")
+);
+
+CREATE UNIQUE INDEX "Cart_userId_key" ON "Cart"("userId");
+CREATE INDEX "Cart_deliveryAddressId_idx" ON "Cart"("deliveryAddressId");
+CREATE UNIQUE INDEX "CartItem_cartId_productId_key" ON "CartItem"("cartId", "productId");
+CREATE INDEX "CartItem_productId_idx" ON "CartItem"("productId");
+
+ALTER TABLE "Cart" ADD CONSTRAINT "Cart_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+ALTER TABLE "Cart" ADD CONSTRAINT "Cart_deliveryAddressId_fkey" FOREIGN KEY ("deliveryAddressId") REFERENCES "DeliveryAddress"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+ALTER TABLE "CartItem" ADD CONSTRAINT "CartItem_cartId_fkey" FOREIGN KEY ("cartId") REFERENCES "Cart"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+ALTER TABLE "CartItem" ADD CONSTRAINT "CartItem_productId_fkey" FOREIGN KEY ("productId") REFERENCES "Product"("id") ON DELETE CASCADE ON UPDATE CASCADE;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index be391b5..6a98e47 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -70,6 +70,7 @@ model User {
   sentInvitations      Invitation[]           @relation("InvitationManager")
   acceptedInvitations  Invitation[]           @relation("InvitationAcceptor")
   messengerConnections MessengerConnection[]
+  cart                 Cart?
   clientOrders         Order[]                @relation("OrderClient")
   managerOrders        Order[]                @relation("OrderManager")
   orderStatusEvents    OrderStatusEvent[]
@@ -91,6 +92,7 @@ model DeliveryAddress {
   unrestrictedValue String?
   fiasId            String?
   defaultForUsers   User[]   @relation("UserDefaultDeliveryAddress")
+  carts             Cart[]
   orders            Order[]
   createdAt         DateTime @default(now())
   updatedAt         DateTime @updatedAt
@@ -179,11 +181,43 @@ model Product {
   isCustomizable  Boolean       @default(false)
   isActive        Boolean       @default(true)
   inventory       ProductStock[]
+  cartItems       CartItem[]
   orderItems      OrderItem[]
   createdAt       DateTime      @default(now())
   updatedAt       DateTime      @updatedAt
 }
 
+model Cart {
+  id                String           @id @default(cuid())
+  userId            String           @unique
+  user              User             @relation(fields: [userId], references: [id], onDelete: Cascade)
+  deliveryAddressId String?
+  deliveryAddress   DeliveryAddress? @relation(fields: [deliveryAddressId], references: [id], onDelete: SetNull)
+  items             CartItem[]
+  createdAt         DateTime         @default(now())
+  updatedAt         DateTime         @updatedAt
+
+  @@index([deliveryAddressId])
+}
+
+model CartItem {
+  id             String   @id @default(cuid())
+  cartId         String
+  cart           Cart     @relation(fields: [cartId], references: [id], onDelete: Cascade)
+  productId      String
+  product        Product  @relation(fields: [productId], references: [id], onDelete: Cascade)
+  productName    String
+  sku            String
+  isCustomizable Boolean  @default(false)
+  quantity       Decimal  @db.Decimal(14, 3)
+  parameters     Json
+  createdAt      DateTime @default(now())
+  updatedAt      DateTime @updatedAt
+
+  @@unique([cartId, productId])
+  @@index([productId])
+}
+
 model Warehouse {
   id        String        @id @default(cuid())
   code      String        @unique
diff --git a/src/resolvers.js b/src/resolvers.js
index 22e042a..c1be655 100644
--- a/src/resolvers.js
+++ b/src/resolvers.js
@@ -76,6 +76,15 @@ function normalizeOptionalText(value) {
   return normalized ? normalized : null;
 }
 
+function normalizeQuantityValue(value) {
+  const normalized = Number(value);
+  if (!Number.isFinite(normalized) || normalized <= 0) {
+    return 0;
+  }
+
+  return Math.floor(normalized);
+}
+
 function isCounterpartyProfileComplete(profile) {
   if (!profile) {
     return false;
@@ -134,6 +143,38 @@ function withDeliveryAddressDefaultFlag(address, defaultDeliveryAddressId) {
   };
 }
 
+function defaultCartParameters(product) {
+  return {
+    width: product.widthMm ?? 100,
+    thickness: product.thicknessMicron ?? 50,
+    color: 'прозрачный',
+  };
+}
+
+const cartInclude = {
+  items: {
+    orderBy: [{ updatedAt: 'desc' }, { createdAt: 'desc' }],
+  },
+  deliveryAddress: true,
+};
+
+async function getOrCreateCart(context, userId) {
+  const account = await context.prisma.user.findUnique({
+    where: { id: userId },
+    select: { defaultDeliveryAddressId: true },
+  });
+
+  return context.prisma.cart.upsert({
+    where: { userId },
+    update: {},
+    create: {
+      userId,
+      deliveryAddressId: account?.defaultDeliveryAddressId ?? null,
+    },
+    include: cartInclude,
+  });
+}
+
 async function enrichMessengerConnectionProfile(prisma, connection) {
   if (
     connection.type !== 'TELEGRAM' ||
@@ -306,6 +347,32 @@ export const resolvers = {
   DeliveryAddress: {
     isDefault: (address) => Boolean(address.isDefault),
   },
+  Cart: {
+    deliveryAddress: async (cart, _, context) => {
+      if (!cart.deliveryAddressId) {
+        return null;
+      }
+
+      const [account, address] = await Promise.all([
+        context.prisma.user.findUnique({
+          where: { id: cart.userId },
+          select: { defaultDeliveryAddressId: true },
+        }),
+        context.prisma.deliveryAddress.findUnique({
+          where: { id: cart.deliveryAddressId },
+        }),
+      ]);
+
+      if (!address) {
+        return null;
+      }
+
+      return withDeliveryAddressDefaultFlag(address, account?.defaultDeliveryAddressId ?? null);
+    },
+  },
+  CartItem: {
+    quantity: (item) => toFloat(item.quantity),
+  },
 
   Query: {
     healthcheck: () => 'ok',
@@ -319,6 +386,11 @@ export const resolvers = {
       });
     },
 
+    myCart: async (_, __, context) => {
+      const user = requireUser(context);
+      return getOrCreateCart(context, user.id);
+    },
+
     myDeliveryAddresses: async (_, __, context) => {
       const user = requireUser(context);
       const [account, addresses] = await Promise.all([
@@ -678,6 +750,171 @@ export const resolvers = {
       });
     },
 
+    addProductToCart: async (_, { productId }, context) => {
+      const user = requireUser(context);
+      const normalizedProductId = normalizeText(productId);
+      if (!normalizedProductId) {
+        throw new Error('Product id is required.');
+      }
+
+      const product = await context.prisma.product.findFirst({
+        where: {
+          id: normalizedProductId,
+          isActive: true,
+        },
+      });
+
+      if (!product) {
+        throw new Error('Product is not available.');
+      }
+
+      const cart = await getOrCreateCart(context, user.id);
+      const existingItem = await context.prisma.cartItem.findFirst({
+        where: {
+          cartId: cart.id,
+          productId: normalizedProductId,
+        },
+      });
+
+      if (existingItem) {
+        await context.prisma.cartItem.update({
+          where: { id: existingItem.id },
+          data: {
+            quantity: Number(existingItem.quantity) + 1,
+            productName: product.name,
+            sku: product.sku,
+            isCustomizable: product.isCustomizable,
+          },
+        });
+      } else {
+        await context.prisma.cartItem.create({
+          data: {
+            cartId: cart.id,
+            productId: product.id,
+            productName: product.name,
+            sku: product.sku,
+            isCustomizable: product.isCustomizable,
+            quantity: 1,
+            parameters: defaultCartParameters(product),
+          },
+        });
+      }
+
+      return context.prisma.cart.findUnique({
+        where: { id: cart.id },
+        include: cartInclude,
+      });
+    },
+
+    updateCartItemQuantity: async (_, { input }, context) => {
+      const user = requireUser(context);
+      const normalizedProductId = normalizeText(input.productId);
+      if (!normalizedProductId) {
+        throw new Error('Product id is required.');
+      }
+
+      const quantity = normalizeQuantityValue(input.quantity);
+      const cart = await getOrCreateCart(context, user.id);
+      const existingItem = await context.prisma.cartItem.findFirst({
+        where: {
+          cartId: cart.id,
+          productId: normalizedProductId,
+        },
+      });
+
+      if (!existingItem) {
+        return cart;
+      }
+
+      if (quantity === 0) {
+        await context.prisma.cartItem.delete({
+          where: { id: existingItem.id },
+        });
+      } else {
+        await context.prisma.cartItem.update({
+          where: { id: existingItem.id },
+          data: { quantity },
+        });
+      }
+
+      return context.prisma.cart.findUnique({
+        where: { id: cart.id },
+        include: cartInclude,
+      });
+    },
+
+    removeCartItem: async (_, { productId }, context) => {
+      const user = requireUser(context);
+      const normalizedProductId = normalizeText(productId);
+      if (!normalizedProductId) {
+        throw new Error('Product id is required.');
+      }
+
+      const cart = await getOrCreateCart(context, user.id);
+      const existingItem = await context.prisma.cartItem.findFirst({
+        where: {
+          cartId: cart.id,
+          productId: normalizedProductId,
+        },
+      });
+
+      if (existingItem) {
+        await context.prisma.cartItem.delete({
+          where: { id: existingItem.id },
+        });
+      }
+
+      return context.prisma.cart.findUnique({
+        where: { id: cart.id },
+        include: cartInclude,
+      });
+    },
+
+    setCartDeliveryAddress: async (_, { addressId }, context) => {
+      const user = requireUser(context);
+      const cart = await getOrCreateCart(context, user.id);
+      const normalizedAddressId = normalizeOptionalText(addressId);
+
+      if (!normalizedAddressId) {
+        return context.prisma.cart.update({
+          where: { id: cart.id },
+          data: { deliveryAddressId: null },
+          include: cartInclude,
+        });
+      }
+
+      const address = await context.prisma.deliveryAddress.findFirst({
+        where: {
+          id: normalizedAddressId,
+          userId: user.id,
+        },
+      });
+
+      if (!address) {
+        throw new Error('Delivery address is not available for this user.');
+      }
+
+      return context.prisma.cart.update({
+        where: { id: cart.id },
+        data: { deliveryAddressId: address.id },
+        include: cartInclude,
+      });
+    },
+
+    clearCart: async (_, __, context) => {
+      const user = requireUser(context);
+      const cart = await getOrCreateCart(context, user.id);
+
+      await context.prisma.cartItem.deleteMany({
+        where: { cartId: cart.id },
+      });
+
+      return context.prisma.cart.findUnique({
+        where: { id: cart.id },
+        include: cartInclude,
+      });
+    },
+
     createMyDeliveryAddress: async (_, { input }, context) => {
       const user = requireUser(context);
       const payload = toDeliveryAddressInputData(input);
diff --git a/src/schema.graphql b/src/schema.graphql
index a0c2b32..2da2997 100644
--- a/src/schema.graphql
+++ b/src/schema.graphql
@@ -191,6 +191,28 @@ type Product {
   availableInWarehouses: [ProductWarehouseBalance!]!
 }
 
+type CartItem {
+  id: ID!
+  productId: ID!
+  productName: String!
+  sku: String!
+  isCustomizable: Boolean!
+  quantity: Float!
+  parameters: JSON!
+  createdAt: DateTime!
+  updatedAt: DateTime!
+}
+
+type Cart {
+  id: ID!
+  userId: ID!
+  deliveryAddressId: ID
+  deliveryAddress: DeliveryAddress
+  items: [CartItem!]!
+  createdAt: DateTime!
+  updatedAt: DateTime!
+}
+
 type OrderItem {
   id: ID!
   productId: ID
@@ -266,6 +288,7 @@ type Query {
   healthcheck: String!
   me: User
   myCounterpartyProfile: CounterpartyProfile
+  myCart: Cart!
   myDeliveryAddresses: [DeliveryAddress!]!
   myMessengerConnections: [MessengerConnection!]!
   myNotificationHistory(channel: MessengerType!, limit: Int = 50): [NotificationHistoryItem!]!
@@ -340,6 +363,11 @@ input CreateMyDeliveryAddressInput {
   fiasId: String
 }
 
+input UpdateCartItemQuantityInput {
+  productId: ID!
+  quantity: Float!
+}
+
 input ReadyOrderItemInput {
   productId: ID!
   quantity: Float!
@@ -400,6 +428,11 @@ type Mutation {
   acceptInvitation(input: AcceptInvitationInput!): User!
   connectMessenger(input: ConnectMessengerInput!): MessengerConnection!
   upsertMyCounterpartyProfile(input: UpsertMyCounterpartyProfileInput!): CounterpartyProfile!
+  addProductToCart(productId: ID!): Cart!
+  updateCartItemQuantity(input: UpdateCartItemQuantityInput!): Cart!
+  removeCartItem(productId: ID!): Cart!
+  setCartDeliveryAddress(addressId: ID): Cart!
+  clearCart: Cart!
   createMyDeliveryAddress(input: CreateMyDeliveryAddressInput!): DeliveryAddress!
   setMyDefaultDeliveryAddress(addressId: ID!): DeliveryAddress!
   deleteMyDeliveryAddress(addressId: ID!): Boolean!