BrainerceUpdate cart item (Storefront)
Changes the quantity, notes or modifier selections of one cart line. quantity: 0 removes the line. Stock is checked again for the new quantity. Present selections replace all existing ones.
For /api/vc/{connectionId}/* routes the connectionId (vc_*) is in the URL path — not a header. Live-mode requests must also send a matching Origin header.
In: header
Path Parameters
Sales channel ID (vc_*), the canonical salesChannelId. connectionId is the deprecated name of the same value and is still the literal path segment.
Cart id, returned by cart (create cart).
Cart line id, the id of an entry in the cart items.
Query Parameters
Language code, for example he. Used only when no Accept-Language header is sent. A language the store does not support, or the store's default language, returns the default text.
Proof that the caller holds this cart. For a guest cart send the cart sessionToken (returned when the cart was created). Required on every cart write when the store runs cart ownership in enforce mode; a missing or wrong token answers 403 CART_ACCESS_DENIED (never 401). A customer cart is proven by the customer Bearer token instead. Send either the cartToken query parameter or the X-Cart-Session header.
Header Parameters
Origin of the storefront page making the call, for example https://shop.example.com. Required: a request with no Origin header is refused with 403. On a LIVE channel its host must equal the channel's registered domain (or one of its subdomains) or match an allowed origin. A TEST channel with no domain accepts any origin; once a domain is set it is matched as on LIVE.
Preferred language, for example he. Its first tag is used when it is one of the store's supported languages other than the default; translated fields are then returned in that language. Falls back to the locale query parameter.
Version of the calling SDK (the Brainerce SDK sends it automatically). Informational: it is recorded on the channel and never changes the response.
Proof that the caller holds this cart. For a guest cart send the cart sessionToken (returned when the cart was created). Required on every cart write when the store runs cart ownership in enforce mode; a missing or wrong token answers 403 CART_ACCESS_DENIED (never 401). A customer cart is proven by the customer Bearer token instead. Send either the cartToken query parameter or the X-Cart-Session header.
New quantity (0 to 1000). Setting quantity: 0 removes the line, same as DELETE.
0 <= value <= 1000New shopper-facing note for this line.
New modifier selections. PRD §7.2.3: present means REPLACE all existing selections on this line. Omit to keep the existing selections unchanged.
New nested combo selections, keyed by parent modifier id. Same REPLACE semantics as selections.
curl -X PATCH "https://api.brainerce.com/api/vc/string/cart/string/items/string?locale=string&cartToken=string" \ -H "origin: string" \ -H "accept-language: string" \ -H "X-SDK-Version: string" \ -H "x-cart-session: string" \ -H "Content-Type: application/json" \ -d '{}'{
"id": "clcrt_abc123",
"sessionToken": "string",
"customerId": "clcustomer_abc123",
"status": "ACTIVE",
"currency": "USD",
"notes": "string",
"analyticsClientId": "clanalyticsclient_abc123",
"analyticsSessionId": "clanalyticssession_abc123",
"subtotal": "39.80",
"discountAmount": "5.00",
"ruleDiscountAmount": "0",
"promoDiscountTotal": "0",
"couponCode": "WELCOME10",
"appliedDiscounts": [
{
"ruleId": "cldr_abc123",
"ruleName": "string",
"type": "PRODUCT_DISCOUNT",
"discountAmount": "5.00",
"description": "string"
}
],
"nudges": [
{
"ruleId": "cldr_abc123",
"text": "string",
"type": "AMOUNT_NEEDED",
"amountNeeded": "12.00",
"quantityNeeded": 1
}
],
"items": [
{
"id": "clx1234567890",
"productId": "clprd_abc123",
"variantId": "clvariant_abc123",
"quantity": 2,
"unitPrice": "19.90",
"currentUnitPrice": "21.90",
"priceChanged": true,
"priceDelta": "2.00",
"priceDirection": "increased",
"isAvailable": true,
"unavailableReason": null,
"discountAmount": "0",
"promoDiscountAmount": "0",
"promoSource": "BUNDLE",
"promoSourceId": "clpromosource_abc123",
"notes": "string",
"metadata": {},
"customizations": {},
"product": {
"id": "clprd_abc123",
"name": "string",
"sku": "MUG-BLU",
"images": [
{
"url": "https://cdn.brainerce.com/products/abc123.jpg",
"alt": "Blue mug"
}
]
},
"variant": {
"id": "clvar_abc123",
"name": "string",
"sku": "MUG-BLU-L",
"image": {
"url": "https://cdn.brainerce.com/products/abc123.jpg",
"alt": "Blue mug"
}
},
"modifiers": [
{
"modifierId": "clmod_abc123",
"modifierGroupId": "clmgr_abc123",
"name": "string",
"priceDelta": "1.50",
"freeApplied": false,
"effectivePrice": "1.50",
"positionInGroup": 0
}
],
"modifiersTotal": "1.50",
"parentCartItemId": "clparentcartitem_abc123",
"createdAt": "2026-01-15T10:30:00.000Z",
"updatedAt": "2026-01-15T10:30:00.000Z"
}
],
"itemCount": 3,
"hasPriceChanges": false,
"hasUnavailableItems": false,
"unavailableItemIds": [],
"expiresAt": "2026-01-15T10:30:00.000Z",
"createdAt": "2026-01-15T10:30:00.000Z",
"updatedAt": "2026-01-15T10:30:00.000Z",
"reservation": {
"hasReservation": true,
"expiresAt": "2026-01-15T10:30:00.000Z",
"remainingSeconds": 540,
"strategy": "ON_CART",
"countdownMessage": "string"
},
"recommendations": {
"recommendations": [
{
"id": "clprd_abc123",
"name": "string",
"slug": "blue-mug",
"basePrice": "24.00",
"salePrice": "19.99",
"images": [
{
"url": "https://cdn.brainerce.com/products/abc123.jpg",
"alt": "Blue mug"
}
],
"type": "SIMPLE",
"inventory": {
"total": 42,
"available": 39,
"trackingMode": "TRACKED",
"inStock": true,
"canPurchase": true
},
"targetVariantId": null,
"requiresVariantSelection": false,
"pinnedVariant": {
"id": "clvar_abc123",
"name": "string",
"attributes": {}
},
"variants": [
{
"id": "clvar_abc123",
"name": "string",
"attributes": {},
"image": {
"url": "https://cdn.brainerce.com/products/abc123.jpg",
"alt": "Blue mug"
},
"price": "24.00",
"salePrice": null
}
],
"relationType": "CROSS_SELL"
}
]
},
"upgrades": {
"upgrades": {}
},
"bundles": {
"bundles": [
{
"id": "clx1234567890",
"name": "string",
"description": "string",
"triggerProductId": "cltriggerproduct_abc123",
"productIds": [
"string"
],
"offeredProducts": [
{
"id": "clprd_abc123",
"name": "string",
"slug": "blue-mug",
"basePrice": "30.00",
"salePrice": "19.99",
"images": [
{
"url": "https://cdn.brainerce.com/products/abc123.jpg",
"alt": "Blue mug"
}
],
"type": "SIMPLE",
"variantId": "clvariant_abc123",
"requiresVariantSelection": false,
"pinnedVariant": {
"id": "clvar_abc123",
"name": "string",
"attributes": {}
},
"variants": [
{
"id": "clvar_abc123",
"name": "string",
"attributes": {},
"image": {
"url": "https://cdn.brainerce.com/products/abc123.jpg",
"alt": "Blue mug"
},
"price": "24.00",
"salePrice": null
}
],
"originalPrice": "30.00",
"discountedPrice": "24.00"
}
],
"discountType": "PERCENTAGE",
"discountValue": "20",
"totalOriginalPrice": "30.00",
"totalDiscountedPrice": "24.00"
}
]
}
}{
"statusCode": 400,
"code": "VALIDATION_FAILED",
"message": "name should not be empty, price must be a positive number",
"timestamp": "2026-08-23T10:15:00.000Z",
"path": "/api/vc/{connectionId}/cart/{cartId}/items/{itemId}"
}{
"statusCode": 403,
"code": "INSUFFICIENT_SCOPE",
"message": "API key does not have the required scope: products:write",
"timestamp": "2026-08-23T10:15:00.000Z",
"path": "/api/vc/{connectionId}/cart/{cartId}/items/{itemId}"
}{
"statusCode": 404,
"code": "RESOURCE_NOT_FOUND",
"message": "Resource not found",
"timestamp": "2026-08-23T10:15:00.000Z",
"path": "/api/vc/{connectionId}/cart/{cartId}/items/{itemId}"
}{
"statusCode": 409,
"code": "CONFLICT",
"message": "The request conflicts with the current state of the resource",
"timestamp": "2026-08-23T10:15:00.000Z",
"path": "/api/vc/{connectionId}/cart/{cartId}/items/{itemId}"
}{
"statusCode": 429,
"code": "RATE_LIMITED",
"message": "Too many requests",
"details": {
"retryAfterSeconds": 12
},
"timestamp": "2026-08-23T10:15:00.000Z",
"path": "/api/vc/{connectionId}/cart/{cartId}/items/{itemId}"
}