Twilio Critical Alert Voice Call Escalation

Overview

This solution adds a last-resort, attention-guaranteed escalation layer for critical (SEV1) alerts using Twilio voice calls. When a critical alert fires, the on-call engineer is first paged by SMS. If they do not acknowledge within a threshold, the flow places an automated Twilio voice call that reads the alert aloud and accepts a phone-keypress to acknowledge. If it is still unacknowledged, the flow escalates to the next responder (SMS + voice) and emails the ops manager as a final fallback. Every state change is posted to Microsoft Teams, and acknowledgement is recorded in a Dataverse ledger so escalation stops the instant someone responds. Why it matters: A sleeping engineer may sleep through an SMS. A phone call that demands a keypress to acknowledge keeps escalating until a human actually responds.

Use Case

An operations / SRE team needs guaranteed escalation for SEV1 incidents: SMS-first, voice-call-with-acknowledgement second, automatic move to the next responder third, and a manager email as the final safety net — with full status visibility in Teams.

Flow Architecture

Environment Variables

Connectors & Connections

Connector	API name	Actions used
Twilio	shared_twilio	SendMessage
Microsoft Teams	shared_teams	PostMessageToConversation
Office 365 Outlook	shared_office365	SendEmailV2
Microsoft Dataverse	shared_commondataserviceforapps	CreateRecord UpdateRecord

Customization Guide

Almost every realistic variant of this flow can be implemented by changing environment variable values. A few cases require small edits inside the flow definition — those are called out explicitly below.

PagerDuty hand-off

For complex escalation policies, hand off to PagerDuty instead of the in-flow chain.

Repeat calls

Add a loop to re-call after N minutes if still unacknowledged.

Conference bridge

For majors, use TwiML <Dial><Conference> to bridge multiple responders.

More tiers

Extend EscalationChain and replace the hard-coded [1] next-responder index with a loop over escalationindex.

Acknowledge by SMS

Wire Twilio inbound-SMS to the receiver flow so a text reply also acknowledges.

Key Expressions

The flow is intentionally light on Power Fx / WDL gymnastics — the heaviest expressions are the branch-name concatenation and the approval outcome check. They are listed below in the order they appear in the flow.

@first(json(variables('varEscalationChain')))

@{json(variables('varEscalationChain'))[1]}

@equals(first(body('Get_Alert_After_SMS')?['value'])?['flowlibs_acknowledged'], 'false')

@{concat('Basic ', base64(concat(parameters('EnvVar_TwilioAccountSid'), ':', parameters('EnvVar_TwilioAuthToken'))))}

From=...&To=...&Twiml=@{encodeUriComponent(outputs('Compose_Voice_TwiML'))}

@triggerFormDataValue('Digits')

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