Runnable examples against the sandbox of Fax for Agents, the fax API built for AI agents.
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Fax for Agents is a fax API, a hosted MCP server and SDKs built so AI agents can send and receive faxes. It is made by JSB Holdings LLC and built by Synapse.
Every example needs a test key (ffa_test_...), created at https://app.faxforagents.com, in
FAXFORAGENTS_API_KEY. A test API key reaches the sandbox only. No carrier, no cost, the destination
number picks the outcome.
| Example | What it shows |
|---|---|
python-agent/ |
An agent loop with the Python SDK: prepare, quote, approval when needed, send, poll |
typescript-agent/ |
The same loop with the TypeScript SDK |
claude-code/ |
A .mcp.json for the hosted MCP server and a prompt that sends a sandbox fax |
n8n/ |
A workflow: inbound webhook, signature check on the raw body, notify |
curl/ |
The raw flow in five calls |
| Destination | Outcome |
|---|---|
+15550000001 |
delivered |
+15550000002 |
busy on attempt 1, delivered on attempt 2 |
+15550000003 |
partial after 3 pages |
+15550000004 |
no answer on all 3 attempts, failed |
+15550000005 |
accepted, no outcome, unknown |
+15550000006 |
provider timeout, unknown |
+15550000007 |
failed with invalid_number |
any other +1 number |
delivered |
A fax is delivered only when the carrier's evidence is on the attempt. partial and unknown
never retransmit on their own. Every example stops there and asks a person.
MIT. See LICENSE. Security reports go to [email protected], see SECURITY.md.