Connect Vapi to Bitcall (Outbound SIP Trunk)

💡 Heads-up: Bitcall is outbound-only today — perfect for Vapi agents that make calls (sales, reminders, surveys, notifications). Inbound numbers (DIDs) are coming soon, and we'll add inbound steps here when they land.

Your Vapi agent does the talking. Bitcall makes sure the call actually reaches a phone. Let's connect them — the outbound way.

• A Vapi account with access to the dashboard and a private API key
• A Bitcall account with a SIP account (username + password) — see Set Up Your First SIP Account
• An outbound Caller ID (CLI) you're allowed to present (number rules depend on the destination country and operator)
• A little Bitcall balance (prepaid — top up with card, PayPal, or crypto)

From your Bitcall SIP account, you'll use:

⚠️ Use username/password authentication, not IP auth. Vapi's own docs note that IP-based auth can misroute on shared SIP servers and is only reliable when a provider gives a dedicated SIP server or unique termination URI. Username/password is the clean path for Bitcall.

Vapi connects to outside carriers using a credential of type byo-sip-trunk. Create it with your Bitcall details (API method shown — there's also a SIP Trunk section in the Vapi dashboard):

curl -X POST "https://api.vapi.ai/credential" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-sip-trunk",
    "name": "Bitcall Outbound Trunk",
    "gateways": [{
      "ip": "gateway.bitcall.io",
      "inboundEnabled": false
    }],
    "outboundLeadingPlusEnabled": true,
    "outboundAuthenticationPlan": {
      "authUsername": "YOUR_BITCALL_SIP_USERNAME",
      "authPassword": "YOUR_BITCALL_SIP_PASSWORD"
    }
  }'

📋 Save the returned Credential ID — you'll need it in the next step.

Note: inboundEnabled is set to false because Bitcall handles outbound today. outboundLeadingPlusEnabled keeps numbers in +E.164 format on the way out.

Vapi needs a "phone number" resource to use as the caller ID (from-number) on outbound calls. Since Bitcall is outbound-only, this is the CLI you want to display — not a Bitcall DID.

curl -X POST "https://api.vapi.ai/phone-number" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-phone-number",
    "name": "Bitcall Outbound CLI",
    "number": "YOUR_OUTBOUND_CALLER_ID",
    "numberE164CheckEnabled": false,
    "credentialId": "YOUR_CREDENTIAL_ID"
  }'

📋 Save the returned Phone Number ID for your test call.

Caller ID on outbound calls depends on the destination country and operator rules — some routes pass your CLI through, some override or sanitize it. Set and manage your CLI here: Change or Manage Your Caller ID.

🎲 Want to rotate caller IDs across a campaign? You can present different CLIs per call from your agent logic.

From the Vapi dashboard, or via the API:

curl -X POST "https://api.vapi.ai/call/phone" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "assistantId": "YOUR_ASSISTANT_ID",
    "customer": { "number": "NUMBER_YOU_ARE_CALLING", "numberE164CheckEnabled": false },
    "phoneNumberId": "YOUR_PHONE_NUMBER_ID"
  }'

📞 Ring… ring… your Vapi agent is now dialling out through Bitcall. 🎉