Update Cart Line
PATCH/api/portal/cart/lines/:line
Set the quantity on an existing line (enforces MOQ + increment). Send the line's last-seen expected_updated_at for shared-cart concurrency: if another buyer changed it first, the write still applies (last-write-wins) but the returned cart's conflict flag is true so the client can refresh.
Request
Responses
- 200
- 401
- 403
- 404
- 422
- 429
OK
Response Headers
Unauthenticated — the bearer token is missing, revoked, expired, or malformed. Never retry automatically; fix the credential. See the Errors guide.
Forbidden — the token lacks a required scope, the endpoint is not available to API tokens, or the user behind the token lacks the permission. A human must adjust the token scopes or user permissions; do not retry.
Not found — no record with the given identifier (or the route does not exist). Verify the ID before retrying.
Validation failed — the body is a field → messages map (Laravel shape) or the platform envelope with a stable machine-readable code. Fix the payload and resubmit.
Rate limited — platform limit is 1,000 requests/min; individual tokens may carry lower limits. Honor the Retry-After header before retrying. See the Rate Limits guide.