---
title: "Apply a coupon to a cart (alias)"
method: POST
path: "/agent/cart/apply-coupon"
tags: ["Checkout"]
---

# Apply a coupon to a cart (alias)

`POST /agent/cart/apply-coupon`

## Request

- Base URL: `https://api.trusteed.xyz/api/v1`
- URL: `https://api.trusteed.xyz/api/v1/agent/cart/apply-coupon`
- Auth: API key in header `X-Agent-Api-Key`

Identical handler to POST /agent/apply-coupon — kept so this path and the one documented in llms-tools.txt never diverge.

## Request body

- ApplyCouponRequest
  - `cartId` string, uuid, required
  - `code` string, required

## Response `200`

Coupon applied (or rejected as invalid) successfully

## Other responses

- `400`: Invalid cartId or code
- `404`: Cart not found (including cross-tenant ownership mismatch)
- `409`: Cart is not open

---

[API](https://skmtc.dev/trusteed/apis/trusteed-api.md) · [All operations](https://skmtc.dev/trusteed/apis/trusteed-api/llms.txt) · [OpenAPI document](https://skmtc.dev/trusteed/apis/trusteed-api/revisions/14ce607accce?raw)