# Blackbird API – Cancel Payment Intent

> Blackbird API – Cancel Payment Intent is a paid API for AI agents from the-stables-blackbird-api.vercel.app, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Cancels a pending (unpaid) Blackbird Payment Intent by ID, preventing it from being charged.

## Facts

- Endpoint: POST https://the-stables-blackbird-api.vercel.app/api/payment_intents/:id/cancel
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blackbird-api-cancel-payment-intent-2e55f568
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5YtYZhsEDc-JsmfX-bW1s

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability blackbird-api-cancel-payment-intent-2e55f568 -d '<json body>'
```

Example prompt: Cancel the pending Blackbird payment intent with ID pi_abc123 — it hasn't been paid yet and I want to make sure it won't go through.

## When to prefer this

Use this endpoint when you need to void a Blackbird payment intent that is still in a pending (unpaid) state — for example after an order cancellation, an accidental creation, or a session timeout. This is the correct endpoint when the intent has NOT yet been paid; for reversing a completed payment, use the refund endpoint instead.

## Known failure modes

- 400 Bad Request if payment intent has already been paid
- 400 Bad Request if payment intent has already been refunded
- 404 Not Found if the payment intent ID does not exist
- 401 Unauthorized if no valid Blackbird identity (wallet via x402/SIWX or member JWT) is provided
- 403 Forbidden if the authenticated identity does not own the payment intent

## How this service works

Cancel a pending Payment Intent. Idempotent; 400 if already paid or refunded. Requires a Blackbird identity: link your agent wallet once at /connect, then call with x402 + SIWX (first call pays, later SIWX-signed calls are free); or pass a member JWT in the X-Blackbird-Token header.

## Output

Returns a confirmation that the payment intent has been cancelled, including its updated status. Returns a 400 error if the intent has already been paid or refunded, since cancellation is only valid for pending (uncharged) intents. The operation is idempotent — cancelling an already-cancelled intent succeeds without error.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blackbird-api-cancel-payment-intent-2e55f568/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from the-stables-blackbird-api.vercel.app](https://www.zero.xyz/host/the-stables-blackbird-api.vercel.app/llms.txt)