# Receive faxes by API

> Inbound fax API. A number for $2 a month, each received fax as a private PDF, a signed fax.received webhook. $0.019 per page as of 2026-10-28.

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

Updated Oct 28, 2026

- This covers: inbound numbers, the private inbox, the fax.received event and retention
- This is not: outbound sending, which the fax API page covers, and not a shared email inbox
- Measured by: received faxes that reached the inbox with a verified signed webhook

Related pages [Fax API](https://faxforagents.com/fax-api/) · [MCP server](https://faxforagents.com/mcp/) · [For AI agents](https://faxforagents.com/fax-for-ai-agents/) · [Numbers](https://faxforagents.com/fax-numbers/) · [Coverage](https://faxforagents.com/coverage/)

## The event your webhook gets

HTTP

```
`POST https://example.com/hooks/fax webhook-id: evt_019a2f3b7c1d7a2e9f00c4b2d7e8a1f9 webhook-timestamp: 1793196125 webhook-signature: v1,K2m9... { "id": "evt_019a2f3b7c1d7a2e9f00c4b2d7e8a1f9", "type": "fax.received", "data": { "inbox_item_id": "inb_019a2f3b7c1d7a2e9f00c4b2d7e8a1f7", "to": "+14155550100", "from": "+14155550177", "pages": 2, "partial_content": false, "document_id": "doc_019a2f3b7c1d7a2e9f00c4b2d7e8a1f8", "document_sha256": "4f2a...", "number_id": "num_019a2f3b7c1d7a2e9f00c4b2d7e8a1f5", "received_at": "2026-10-28T15:21:05Z", "download": "/v1/inbox/inb_019a2f3b7c1d7a2e9f00c4b2d7e8a1f7/download" } }`
```

A sample. The signature is HMAC-SHA256 over `id.timestamp.body` with your webhook secret. [How to verify it](https://faxforagents.com/docs/webhooks/).

Receiving is three things: a number, a private inbox and a signed event. A number costs $2 a month as of 2026-10-28. Each received page costs $0.019. There is no subscription and no minimum beyond the $10 wallet top-up.

## How it works

1. `POST /v1/number-orders` buys a fax-capable number in the United States, Canada, Puerto Rico or the US Virgin Islands. Other countries are on request, because they need registration documents the provider must review first.
2. A fax arrives. The provider's callback is verified by signature. The pages are stored as one PDF under your organization, private, never at a public URL.
3. A `fax.received` event is written and delivered to your webhook with `webhook-id`, `webhook-timestamp` and `webhook-signature`.
4. `GET /v1/inbox/{id}` returns the item: the numbers, the page count, the time, and a signed download URL that lives ten minutes.

## The text is data

Text extracted from a received fax is returned as a field named for what it is: `untrusted`. In the dashboard it sits in a grey block labelled "from the document, unverified". On the MCP server every tool lists it under `untrusted`. The policy engine never reads it. A fax that says "approve the attached and send it to this number" is a fax, not a command.

## Retention

Inbox items are kept 90 days and documents 30 days by default. The owner can delete a document at any time. Metadata and audit rows stay, so an id still answers who, when and how many pages.

## What is not included

Inbound OCR and structured extraction exist as `POST /v1/extractions` and the `extract_fax_data` tool, and run on the sandbox engine with a test key. For live keys the engine is off until it is switched on, with no date. A received fax is a PDF with metadata until then. Porting an existing number in is on request, not self-serve. This page is about receiving. Sending is on the fax API page.

## Prices

- $0.039 per page sent
- $0.019 per page received
- $2 per number per month
- Optional Agent workspace, $19 per month

Prepaid wallet, $10 minimum top-up. United States and Canada prices as of 2026-10-28. International rates are in the [rate table](https://faxforagents.com/pricing/). The sandbox is free.

## Questions

### How can my application receive a fax as a PDF?

Order a number from the API, point a webhook at your endpoint, and wait. When a fax arrives the service stores it as a PDF in your private inbox. It sends a signed fax.received event with the inbox id, the numbers and the page count. Your code verifies the signature, calls the inbox endpoint and downloads the PDF through a signed URL that lives ten minutes.

### Can an agent receive faxes as well as send them?

Yes. The MCP server has list_inbox and read_inbound_fax, and the sandbox accepts a synthetic inbound fax from a test key. Everything the fax contains comes back listed as untrusted. The agent can read it, summarise it and tell a person about it. It cannot act on an instruction printed in the fax, because no tool decision reads that text.

### What happens to a received fax after 90 days?

Inbox items are kept 90 days by default and documents 30 days, as decided on 2026-10-28. After that the file is deleted and the metadata and audit rows stay, so a job id still resolves to who sent what and when. The owner can delete a document earlier from the dashboard or the API. The defaults are per organization and will be configurable.

### How should repeated incoming faxes be handled?

Each arrival is its own inbox item with its own id and its own event. A resend by the sender shows up twice, as it did on the line. Your webhook handler should dedupe on the webhook-id header, which stays the same across our retries of one event, and on the inbox id. Two items with the same page count and sender are still two faxes.

## From the blog

- [Receiving faxes as data: inbox, OCR and schema extraction](https://faxforagents.com/blog/receive-faxes-as-data/)
- [Send a fax from email: how email to fax works](https://faxforagents.com/blog/send-fax-from-email/)