Voice overview
Bird Voice lets you place calls to phone numbers. Your phone system connects to Bird, and Bird routes each call through a carrier to the public telephone network, the PSTN.
The connection between your phone system and Bird is a SIP trunk. SIP (Session Initiation Protocol) is the language phone systems speak to set up calls, and a trunk is the line those calls travel over. Bird issues your workspace a trunk address, and you point your phone system at it. A Bird trunk carries calls in one direction: from your equipment out to the telephone network.
Coming soon: placing calls straight from the browser, over WebRTC.
How a call is placed
Your phone system starts and ends every call. To place one, it sends a call setup request, a SIP INVITE, to your trunk's address. Bird checks the call before any carrier sees it (the caller ID you present, the destination country, your limits and balance), then routes it to a carrier and relays the audio. When the call ends, Bird writes the call record you see on the Calls page and emits a voice_call.ended event.
A call that fails a check is refused before a carrier is involved, and the specific reason goes onto the call record. Placing calls covers what Bird reads off each call, and Rejected calls lists every refusal reason and what to do about it.
Before your first call
Three things are yours to set up before a call goes through:
- Create a SIP trunk and allow your equipment on it, with an IP range or an API key.
- Verify a caller ID: register the number you present as the caller and confirm it with a verification call. Calls go out only under numbers you have verified.
- Enable your destinations: turn on the countries you call.
Place your first call runs through all three and ends with a real call, in about ten minutes.
The Voice app in the dashboard
| Page | What it is for |
|---|---|
| Metrics | Call volume, answer rate, and call duration over time, with top countries and SIP response codes |
| Calls | Every call the workspace placed, with usage totals for the month |
| SIP Trunks | Your trunks, their SIP domain, and who may send traffic to them |
| Destinations | The countries your workspace may call, off by default |
| Trust | The caller IDs you have proven you own and may present |
Visibility
Every call Bird admits produces a record, whether it connected, rang out, or was refused:
- Call log: the per-call view on the Calls page. Status, both numbers, the trunk the call came in on, the SIP response it ended on, answer and end times, billable time, and cost. Filter it, then export the result as CSV.
- Voice events: voice_call.initiated, voice_call.answered, and voice_call.ended delivered to your own endpoint, so your systems learn about a call without polling.
Limits
Calls in progress, new calls per second, and daily voice spend all run against limits. The amounts depend on your plan, and Rate limits covers how Bird resolves one and how to have it raised.
Next steps
| Page | What it covers |
|---|---|
| Place your first call | From an empty workspace to a ringing phone in about ten minutes |
| SIP trunks | Creating a trunk, its connection details, and controlling who may send |
| Placing calls | What Bird expects on the INVITE, and what a call costs |
| Caller IDs | Registering a number and proving you own it with a verification call |
| Voice destinations | Turning on the countries you call, and what high risk means |
| Call log | Browsing, filtering, and exporting your call records |
| Voice events | The three call events and their payloads |
| Troubleshooting | Diagnosing a call that does not go through, from its symptom |
| Webhooks & events | Endpoint setup, signature verification, retries, and replay |