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When Twilio runs into a problem while handling an SMS, voice, or other request, it logs an event in the Debugger at one of two levels: Error (Twilio could not process the request) or Warning (Twilio could still process it). Use the Error webhook in the Twilio Console to send Error-level events to Flashduty On-call:
  • Events with the same error code on the same Twilio account merge into one alert, for example a run of 11200 errors caused by your application URL returning 404
  • Warning-level events do not create alerts
The Error webhook is available in every Twilio region (US1, IE, and AU).

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In Flashduty On-call

You can get the integration push URL in either of the following ways.

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Use a dedicated integration

  1. In the Flashduty console, go to Channels and open a channel
  2. Select Configuration → Integrations → Private integration, then click Add an integration
  3. Select Twilio and click Save
  4. Open the new integration card and copy the push URL

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Use a shared integration

  1. In the Flashduty console, go to Integration Center → Alert Events
  2. Select Twilio and enter an integration name
  3. Configure the default route and select a channel. You can add more rules under Routes after creation
  4. Click Save and copy the generated push URL

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Configure Twilio

1

Set the Error webhook

  1. Sign in to the Twilio Console and go to Monitor → Error webhook
  2. Enter the full push URL of the Flashduty integration as the webhook URL and save
2

Test

The Error webhook has no “send test notification” button. To produce a real Error event:
  1. Under Phone Numbers, open a number and set the A call comes in URL to an address that returns 404, such as https://example.com/not-found
  2. Call the number. Twilio fails to fetch the URL and logs error 11200 in the Debugger
  3. After a few seconds, an alert titled Twilio error 11200: ... appears in Flashduty
Restore the number’s original URL when you are done.
3

Turn on the auto-resolve timeout

Debugger events are one-time log entries. Twilio sends nothing when an error stops occurring, so these alerts never recover on their own. In the channel that receives these alerts, turn on the auto-resolve timeout. We suggest a timeout of 2 hours, counted from Incident trigger. Closing the incident also closes its alerts; if the error is still occurring, the next event opens the alert again.

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Payload

Twilio sends one Debugger event per request. The body is application/x-www-form-urlencoded, and Payload is JSON: Every alert also carries the label source=twilio, and its description links to the error code in the Twilio error dictionary (https://www.twilio.com/docs/errors/<error code>). Example title: Twilio error 11200: An attempt to retrieve content from https://app.example.com/voice returned the HTTP status code 404.

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Alert Key

Flashduty computes the Alert Key from AccountSid and Payload.error_code, not from the event ID Sid:
  • Events with the same error code on the same account merge into one alert. The alert’s title, description, and labels show the latest event
  • Different error codes, and different accounts (including different subaccounts), are different alerts
  • This matches how Twilio Alarms count errors per account and per error code

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Status and severity

An Error event is rejected if it lacks AccountSid or Payload.error_code, or if Payload is not valid JSON.

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FAQ

Twilio logs problems it could still process as warnings, such as TwiML validation warnings. They are frequent and rarely need the on-call engineer right away, so Flashduty accepts them without creating an alert. You can still see them in the Twilio Debugger.
Events with the same error code on the same account merge into one alert, whose event count grows instead of a new alert opening for each failure. With the auto-resolve timeout on, the incident closes after the timeout; if the error is still occurring, the next event opens a new alert.
No. Flashduty identifies the integration by the integration_key in the push URL and does not verify the X-Twilio-Signature header. Keep the push URL as secret as a key.

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Troubleshooting

  • Errors appear in the Twilio Debugger but not in Flashduty: make sure the URL under Monitor → Error webhook is complete (including integration_key) and that the event level is Error
  • Requests are rejected (4xx): make sure the push URL belongs to a Twilio integration, not another integration
  • Alerts never close: turn on the auto-resolve timeout in the channel