# Verify a sender

> Every verify a sender endpoint, generated from the API's own schemas.

Base URL `https://pidgeon.ai/api/v1`. Every request carries `Authorization: Bearer pgn_live_…`. The machine-readable version of this page is https://pidgeon.ai/openapi.json.

## POST /verify

Check who sent a message

Public, with no key. Send a raw message, or its headers alone; the answer says whether an AI agent sent it, on whose behalf, and whether its signatures hold — the signed agent declaration (`Agent-of` under an aligned DKIM signature) and the `Post-Envelope` — for Pidgeon’s mail and any other signer using the same formats. Act on `verdict`. Pass `recipient`, the address it reached you at, to catch a signed message replayed to you. Nothing sent is stored. Limited per IP; a key may be sent and is not required.

**Body**

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `message` | string | yes |  |
| `recipient` | email | no |  |

**Responses**

- `200` The verdict.
- `400` The request is not valid. `error.field` names the input at fault when there is one.
- `401` No API key, or one that is not valid.
- `403` Refused. `error.code` says why: `forbidden` when this key may not do this or the account is on hold, `abuse_blocked` when a limit says no.
- `404` No such resource, or one this key cannot reach. The two answer the same, so treat a 404 as “not available to you” rather than “does not exist”.
- `409` It conflicts with what is there: it already exists, or the `etag` you sent is not the current one.
- `429` Rate limited. `X-RateLimit-Reset` says when to retry.
- `500` Something went wrong on our side. Retry; if it keeps happening, tell us.
- `503` Something this needs is not answering right now. Retry in a moment.