# POST /api/v1/chat/join

Auth: public

HTML: https://cooperemail.com/docs/reference/chat-join

## Summary

Join with a pair code. Without a key, Cooper creates an account, an inbox, and an API key returned once. The full owner address is not returned.

## Request

```json
{
  "code": "cpair_example"
}
```

## Response

The OpenAPI document does not declare a JSON response schema for this call. The summary is the contract.

## Errors

- HTTP 400 invalid_pair_code

The live `message` is the sentence for that code. Branch on `code`.

```json
{
  "error": {
    "type": "invalid_request",
    "code": "invalid_pair_code",
    "docs_url": "https://cooperemail.com/docs#invalid_pair_code"
  }
}
```

## Idempotency

This route does not document Idempotency-Key or client_id.