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SignalWire Compatibility API

SignalWire’s “Compatibility” endpoints mimic the old Twilio Fax API. Faxbot uses a tokenised MediaUrl so SignalWire can fetch documents securely.

Gather before you start

  • Space URL (e.g., example.signalwire.com)
  • Project ID and API Token
  • Public HTTPS URL for callbacks and PDF fetches

Configure with the Setup Wizard

  1. Admin Console → Setup Wizard
  2. Choose SignalWire Compatibility
  3. Enter Space URL, Project ID, API Token, and default From number
  4. Provide your public URL; the wizard computes the MediaUrl that SignalWire fetches
  5. Apply & reload the config

{: .note } Need a quick tunnel? Follow Public Access & Tunnels.

Send & monitor

  • Send Fax uploads PDF/TXT, then Faxbot hosts the document at /fax/{jobId}/pdf?token=…
  • SignalWire fetches the MediaUrl via HTTPS
  • Status callbacks hit /signalwire-callback; enable signature verification by setting the signing key in Settings → Backends → SignalWire
  • Watch status transitions in Jobs with provider-specific troubleshooting links

How it works (under the hood)

  • Faxbot mints a short‑TTL tokenised MediaUrl and includes it in the create‑fax request
  • SignalWire fetches the MediaUrl via HTTPS; Faxbot returns the PDF if and only if token and TTL match
  • Optional HMAC verification protects callbacks (X-SignalWire-Signature when configured)
  • Admin coverage: Diagnostics shows callback URL and signature settings; Jobs reveal provider SID

Troubleshooting

  • 403 fetching MediaUrl → Token expired or PUBLIC_API_URL mismatch; reopen the job to mint a new link
  • 401 from SignalWire → Regenerate the API token in the SignalWire console and rerun the wizard
  • No callbacks → Confirm the StatusCallback URL is set in the SignalWire portal (the wizard shows the expected value)

References