FaxDev: one fax workflow for APIs, agents, and people

Field notes

The API walkthrough uploads a PDF, creates a fax with an idempotency key, and then checks the resulting status; the page also describes signed webhooks as an alternative to polling. An MCP example gives an agent separate send and read actions, while a reseller-console example breaks out retail, wholesale, and margin across accounts. The site says sandbox keys exercise the pipeline without placing a call.