Twilio integration

Twilio is the simplest of the three credential shapes: two fields, `account_sid` and `auth_token`, and nothing else. There is no application id to find, which is the main practical difference from Telnyx and Plivo.

Validation calls `GET /2010-04-01/Accounts/{SID}.json` with the pair. Rexa stores the account SID, friendly name, status and type from the response, so the dashboard can show which account you are connected to. A wrong pair returns `invalid_api_key`; a SID that does not resolve returns `invalid_application` with a reminder that Twilio account SIDs begin with `AC`.

A suspended or closed account is treated as its own case rather than a generic error. It maps to `application_disabled`, so you learn about it while saving the credential instead of when the first campaign fails to dial.

Open the Twilio Console and copy the Account SID and Auth Token from the account you want calls to run on. In Rexa, add a Twilio provider and paste both. Validation runs on save and again on Test connection.

Once saved, numbers on that account appear on `GET /v1/phone-numbers` with `provider` set to `twilio`, and the `label` field is taken from each number’s Twilio friendly name — so naming numbers sensibly in Twilio pays off in Rexa’s from-number picker.

For inbound calls, point the number’s voice webhook at Rexa’s Twilio inbound endpoint. Outbound needs nothing further.

Two things worth knowing before you choose. First, caller-ID name is not surfaced: `GET /v1/phone-numbers` returns `caller_id_name` as `null` for every Twilio number, because Rexa only populates it for Telnyx.

Second, there is no inventory-scoping field. Plivo credentials accept an optional Application ID that narrows which numbers Rexa can see; Twilio credentials do not, so whichever account the SID belongs to, all of its numbers are visible. If you need that separation, use a Twilio subaccount and store that subaccount’s own SID and token.

If you would rather keep your own telecom account, you can connect Telnyx, Twilio or Plivo and run calls on your existing numbers. Rexa’s per-minute rate is the same either way, and your carrier bills you directly for their per-leg cost.

Every tenant-and-carrier pair has its own circuit breaker. Five consecutive dispatch failures open it, and while it is open Rexa refuses to dispatch through that carrier at all. Sixty seconds later the breaker moves to half-open, which admits exactly one probe call. A successful probe closes it; a failed probe re-opens it and restarts the sixty-second clock, keeping the failure count at the threshold so the next recovery needs a good probe rather than another five failures.

The breaker is scoped per tenant, so another account’s bad afternoon never takes your carrier out of rotation. If you have a second carrier configured, the router skips the open one and tries the next by priority.