Customisation

Endpoint URL and query parameters

Your URL can carry per-call values that Fonada substitutes before connecting, so your server can route or authenticate from the query string alone:

wss://voice.example.com/stream?uuid={session_id}&caller={customer_phone}

Available substitutions:

• {session_id}
• {customer_phone}
• {business_phone}
• {client_id}
• {call_direction}

Plus any agreed metadata key.

Fonada also supports the endpoint being chosen per call rather than fixed, where different campaigns, numbers, or brands should reach different URLs.

Field names

If your service expects different field names, Fonada renames them. For example, to receive CLI, calling_party, and direction:

{
  "type": "session_start",
  "session_id": "1711234567.42",
  "client_id": "acme-voicebot",
  "CLI": "919876543210",
  "calling_party": "18001234567",
  "direction": "outbound",
  "audio": { "codec": "pcm16", "input_sample_rate": 8000, "output_sample_rate": 8000, "channels": 1 },
  "metadata": { "language": "en" }
}

Fonada can also add fixed literal fields — such as an account identifier or API version — or combine values. Only type and audio are fixed.

Metadata

Arbitrary key/value pairs delivered in session_start.metadata — language, agent or prompt identifier, tenant reference, campaign name. Each key can be static for your account or set per call. You specify which keys are required.

Call direction

Both the field name and the exact strings are yours to choose. Fonada can also place the direction in the URL query string instead of, or in addition to, the payload.

Sample rate, chunk size, and audio encoding

All per-account settings — covered in Messages Fonada sends and Audio.