Developers
The JamFax fax API lets your software send faxes, check their status and download documents over HTTPS with an API key. The base URL is https://api.jamfax.com/v1.
Last reviewed October 25, 2026.
Create a key in the app (Settings, then API keys), then post your documents:
curl https://api.jamfax.com/v1/fax/faxes \
-H "Authorization: Bearer $JAMFAX_KEY" \
-H "Idempotency-Key: invoice-1042" \
-F from=+13055550100 -F to=+13055550142 \
-F "documents[]=@invoice.pdf"Check a fax with GET /v1/fax/faxes/{id}. Send an Idempotency-Key with every fax so a retry never sends it twice.
fax.send: send faxes.fax.read: list lines and faxes, and download documents.fax.contacts: manage your fax contacts.Get a signed webhook the moment a fax arrives or finishes: fax.received, fax.delivered and fax.failed. Webhooks are for business accounts. Every delivery is signed, so you can check it came from JamFax.
The developer guide has every endpoint, the webhook signature check and the limits. The API reference and OpenAPI file are in the app.
https://api.jamfax.com/v1. Requests use an API key sent as a Bearer token.
Each key has scopes. fax.read lists lines and faxes and downloads documents, fax.send sends faxes, and fax.contacts manages your fax contacts. Tick only what your software needs.
In the JamFax app, under Settings, then API keys. The key is shown once, so copy it when you create it.
Yes. Signed webhooks for fax.received, fax.delivered and fax.failed are available on business accounts.
A fax sent through the API is billed like one sent from the browser: it uses your plan's pages, or your Pay-as-you-go credit.