Phone call and SMS alerting that wakes the right engineer

Which channels can Oncallz page on?

Four channels, chosen per severity in the Paging & SMS settings. Severities follow the PagerDuty Events API levels: critical, error, warning and info. A common setup is a phone call plus SMS for critical, SMS and push for error, and push or email only for the rest.

Escalation policy steps can override the channels for that step, for example to call a team lead even when the severity matrix would only send a push.

• Phone call — Twilio dials the engineer, reads the severity, title and team aloud and waits for a key press.
• SMS — a text message with the incident details, sent through your Twilio or Vonage account.
• Push — a notification to the Oncallz iOS app. The Android app is in closed beta.
• Email — always on for every severity, as a baseline record.

How does the phone call work?

When the severity matrix says “call”, Oncallz asks Twilio to dial the on-call engineer. On answer, a text-to-speech voice reads the incident: severity, title and team. The engineer presses 2 to acknowledge, 4 to escalate to the next person or 6 to mark it resolved.

The action lands on the incident timeline as theirs, exactly as if they had clicked it in the app.

The phone rings for about 29 seconds. Answering machine detection hangs up on voicemail before the prompt plays and logs the call as voicemail.

Every outcome — answered, not picked up, declined or failed — appears on the incident timeline and in the call log, so you can see whether a page actually reached a person. Calls are spoken in each user’s language, English or Turkish.

Why bring your own Twilio or Vonage account?

Oncallz does not resell SMS messages or voice minutes. You connect your own provider under Settings → Paging & SMS: Twilio for SMS and phone calls, or Vonage for SMS. Credentials are checked with the provider before saving and stored encrypted.

Put plainly, you need a Twilio or Vonage account, and you pay them for the messages and calls you send.

Each engineer verifies their phone number once with a one-time code before SMS or calls go to it. That verification runs on Oncallz’s own Twilio Verify service, not on your account.

• You pay carrier rates directly to Twilio or Vonage, with no Oncallz markup on messages or minutes.
• Alerts come from your own number or sender ID, which engineers can save to their contacts and allow through their phone’s quiet modes.
• Delivery logs, number registration and country coverage stay in your own provider console.
• Push notifications and email need no provider at all.

How are alert storms handled?

A burst of alerts should not mean a burst of phone calls. Several controls keep paging proportionate:

• Call cooldown — ring each engineer at most once per N minutes. Other incidents still open and still send push and email.
• Duplicate grouping — repeated events fold into one open incident instead of paging again.
• Call-suppression rules — mute only the phone call for alerts that match a regex you define.
• Maintenance windows — drop, quiet or downgrade matching events during planned work.
• AI noise filter — optionally let AI investigation skip the call for alerts it judges to be clear noise. Off by default.

Can I test paging before a real incident?

Yes. The settings page has a test SMS, a test call and a test push button, each sent to your own verified phone or registered devices. Use them after connecting the provider and whenever you change numbers. The test call plays a short message confirming that phone paging is set up correctly.