# API reference

> From the OpenAPI 3.1 snapshot of 2026-10-30. 146 operations in 18 groups. Read it as plain HTML or open the interactive explorer.

Page: https://faxforagents.com/docs/api/
Last changed: 2026-10-28

Updated Oct 28, 2026

The REST API is at `https://api.faxforagents.com/v1`. The reference is built from the server's own OpenAPI 3.1 document, snapshot of 2026-10-30, version 1.3.3. 146 operations in 18 groups and 147 schemas.

## How do I read the reference?

- [The full reference as plain HTML](https://faxforagents.com/docs/api/reference/): every operation, parameter, body, response and schema. Loads with no JavaScript and reads well on a phone.
- [openapi.json](https://faxforagents.com/openapi.json) and [openapi.yaml](https://faxforagents.com/openapi.yaml): the document itself, for a generator or a client.
- The interactive explorer below, which loads a third-party viewer on demand.
- [github.com/faxforagents/openapi](https://github.com/faxforagents/openapi): the same document in a public repository, with a changelog per version.

## How do I authenticate?

`Authorization: Bearer ffa_test_...` or `X-API-Key: ffa_test_...` on every call. Test keys reach the sandbox, live keys reach the carrier. Signed upload and download URLs take no key. Every mutating call accepts an `Idempotency-Key`.

## Groups

- [agents](https://faxforagents.com/docs/api/reference/#tag-agents)
- [identity](https://faxforagents.com/docs/api/reference/#tag-identity)
- [approvals](https://faxforagents.com/docs/api/reference/#tag-approvals)
- [auth](https://faxforagents.com/docs/api/reference/#tag-auth)
- [billing](https://faxforagents.com/docs/api/reference/#tag-billing)
- [platform](https://faxforagents.com/docs/api/reference/#tag-platform)
- [extractions](https://faxforagents.com/docs/api/reference/#tag-extractions)
- [numbers](https://faxforagents.com/docs/api/reference/#tag-numbers)
- [documents](https://faxforagents.com/docs/api/reference/#tag-documents)
- [events](https://faxforagents.com/docs/api/reference/#tag-events)
- [quotes](https://faxforagents.com/docs/api/reference/#tag-quotes)
- [faxes](https://faxforagents.com/docs/api/reference/#tag-faxes)
- [inbox](https://faxforagents.com/docs/api/reference/#tag-inbox)
- [members](https://faxforagents.com/docs/api/reference/#tag-members)
- [organizations](https://faxforagents.com/docs/api/reference/#tag-organizations)
- [policies](https://faxforagents.com/docs/api/reference/#tag-policies)
- [sandbox](https://faxforagents.com/docs/api/reference/#tag-sandbox)
- [webhooks](https://faxforagents.com/docs/api/reference/#tag-webhooks)

## Interactive explorer

The explorer is a 3 MB third-party viewer, loaded only when you ask for it, pinned to one version and checked against its published hash. It reads `/openapi.json` from this site and lets you try calls with your own key. Your API key goes to api.faxforagents.com and nowhere else.