Skip to main content
Use the mintfax API to send a document to a fax number and track its delivery. Start with the free sandbox, then use a live API key when you are ready to send real faxes.

​
Getting started

  • Sandbox - create an account and get an API key to test simulated fax deliveries.
  • Coding agents - use the OpenAPI specification, structured errors, and repeatable sandbox scenarios.
  • Data controls - configure content retention and export your audit log. The retention guide explains zero-footprint mode and which data it deletes.

Quickstart

Register and send a simulated fax

API reference

Full endpoint documentation

Error catalog

Every error code and what to do about it

Webhooks

Receive delivery updates

​
How it works

  1. Create an account - POST /account/register + verify email code to get your API key
  2. Send a fax - POST /fax with a file attachment queues the fax
  3. Track delivery - poll GET /fax/{id} or receive a webhook
  4. Credits - pay for delivery from a prepaid balance
A credit hold is placed when you submit a fax. If delivery succeeds, the hold is captured as a charge. If delivery permanently fails, the hold is released back to your balance. You are never charged for failed deliveries.
Last modified on July 20, 2026