A fax API built for AI agents
Updated
One call to send
curl https://api.faxforagents.com/v1/faxes \
-H "Authorization: Bearer ffa_test_..." \
-H "Idempotency-Key: order-4411-fax" \
-H "Content-Type: application/json" \
-d '{"quote_id": "quote_019a2f3b7c1d7a2e9f00c4b2d7e8a1f6"}'- Job
- fax_019a2f3b7c1d7a2e9f00c4b2d7e8a1f6
- To
- +1 415 555 0142
- From
- +1 628 555 0199
- Pages
- 3 of 3
- Provider ref
- TX-88f2a1
- Document sha256
- 9b1c4e2a...
- Amount captured
- $0.117
- Timestamp
- 2026-10-28 14:02:31 UTC
Fax for Agents is a REST API at https://api.faxforagents.com/v1 for sending and receiving faxes, with a hosted MCP server and SDKs on top of it. Pricing is per page and prepaid. $0.039 per page sent and $0.019 per page received in the United States and Canada, as of 2026-10-28. It is built for software that acts on its own. Every mutating call takes an Idempotency-Key. Every send is quoted before it is charged. Every job ends with evidence a person can check.
A fax API is a web service that sends and receives faxes through HTTP calls. Software that uses one needs no fax machine, no phone line and no online fax inbox. Fax for Agents is a cloud fax API for programs and agents, not an online fax service for people.
What a job looks like
A send has five steps and each one is a call you can make with curl.
- Upload a PDF or an image, or post text, Markdown or HTML and let the API render it. The document gets a sha256 and a page count.
- Quote the document to one destination. The quote fixes the price, the pages and the sender for ten minutes.
- Send the quote. The wallet holds the amount. A test key is sent at once. A live API key needs an approval or a policy that allows it.
- Watch the job. It moves through
queuedandactiveand endsdelivered,partial,failedorunknown. Webhooks carry each change with a signature. - Read the receipt. Provider reference, document hash, pages, amount captured, timestamp.
Receiving
A number costs $2 a month as of 2026-10-28 and receives at $0.019 per page. Every received fax lands in a private inbox as a PDF behind a short-lived signed URL, and a signed fax.received event goes to your webhook. The text of a received fax is data. It is listed as untrusted on every MCP result and it never reaches a policy decision.
What is not included
Fax for Agents is not an online fax service for people, and it is not a HIPAA service. It sends PDF, PNG, JPG and TIFF uploads and documents rendered from text, Markdown and HTML. Office formats are not accepted. Inbound numbers are available in the United States, Canada, Puerto Rico and the US Virgin Islands at launch, elsewhere on request.
Prices
- $0.039per page sent
- $0.019per page received
- $2per number per month
- OptionalAgent 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. The sandbox is free.
Questions
Can an AI agent send a fax?
Yes, through this API or its MCP server. The agent uploads or renders a document, asks for a quote, and sends the quoted job. A person sets the limits first. Either an approval is given for that exact document and recipient, or a delegated policy allows the send on the server. The job ends in one of six states and a receipt records the provider reference, the document hash, the amount and the time.
What does fax delivered actually mean here?
It means the provider reported every page as received by the remote machine, and that report is stored on the attempt. The receipt names the provider reference and the completion time. It does not mean a person read the document. A job without that report stays active or ends unknown, and the site never writes delivered without the evidence behind it.
Is the fax API a HIPAA service?
No. Fax for Agents is not a HIPAA service and does not sign business associate agreements. Protected health information must not be sent through it. The acceptable use policy says so plainly. Documents are processed in the EU, kept 30 days by default and deletable by the owner at any time. None of that makes the service suitable for PHI.
How do I test a fax integration without contacting real numbers?
Use a test key. It is tied to the sandbox, where each scripted destination ends in a chosen state, from delivered to unknown. The sandbox fires the same signed webhooks as a live send and costs nothing. Every test organization starts with a seeded test wallet, so the hold, capture and release path runs exactly as it will with real money.