Account Lifecycle Integration Guide

This guide covers how to wire Exotel's communication products into a full user lifecycle system — from signup verification through churn prevention. Audience: engineers integrating Exotel APIs into a product backend.

All 8 products are covered: Verify, Voice, SMS, WhatsApp, Campaigns/Engage, Voicebot, CQA, and Chatbot.

1. System Architecture

Component Overview

┌──────────────────────────────────────────────────────────────────────┐
│                        Your Application Layer                         │
│                                                                        │
│   ┌──────────────┐    ┌──────────────┐    ┌──────────────────────┐  │
│   │  Product      │    │  Lifecycle   │    │  Webhook Handler     │  │
│   │  Backend      │◄──►│  State Store │◄───│  (POST /webhooks/*)  │  │
│   │  (REST API)   │    │  (DB / Redis)│    └──────────────────────┘  │
│   └──────┬───────┘    └──────────────┘             ▲                 │
│          │                                           │                 │
└──────────┼───────────────────────────────────────────────────────────┘
           │ outbound API calls                        │ inbound webhooks
           ▼                                           │
┌──────────────────────────────────────────────────────────────────────┐
│                          Exotel Platform                              │
│                                                                        │
│  ┌──────────┐  ┌───────┐  ┌────────┐  ┌──────────────────────────┐  │
│  │  Verify  │  │  SMS  │  │ Voice  │  │  WhatsApp Business API   │  │
│  │  (OTP)   │  │  API  │  │  API   │  │  (Templates/Interactive) │  │
│  └──────────┘  └───────┘  └────────┘  └──────────────────────────┘  │
│                                                                        │
│  ┌────────────┐  ┌──────────┐  ┌──────────┐  ┌────────────────────┐ │
│  │ Campaigns  │  │Voicebot  │  │ Chatbot  │  │  CQA               │ │
│  │ (Engage)  │  │  (AI IVR)│  │(Web/WA)  │  │  (Quality Scoring) │ │
│  └────────────┘  └──────────┘  └──────────┘  └────────────────────┘ │
└──────────────────────────────────────────────────────────────────────┘
           │                                           │
           ▼                                           │
     End Users (phone, WhatsApp, web)  ────────────────┘

Where Exotel Sits in Your Stack

CRM / User DB  ──►  Your Backend  ──►  Exotel APIs  ──►  End User
                          ▲                 │
                          └─────────────────┘
                           Webhook callbacks
                        (delivery, call events,
                         bot sessions, CQA scores)

Your backend is the orchestrator. Exotel is the communication execution layer. You own lifecycle state; Exotel fires events back to you via webhooks that keep your state in sync.

Webhook Event Bus Pattern

Register a single base path (e.g., https://api.yourapp.com/webhooks/exotel) with sub-routes per product. Each incoming webhook should:

Validate the signature (HMAC-SHA256 on X-Exotel-Signature / X-CQA-Signature)
Respond 200 OK within 5 seconds (async processing)
Deduplicate on the event's unique ID before processing (see §7)

2. Lifecycle State Machine

States

ACQUIRED ──► ONBOARDING ──► ACTIVATED ──► ENGAGED
                                             │
                                        AT_RISK ──► CHURNED ──► OFFBOARDED

State Transition Table

Transition	Trigger Event	Exotel Product	API Call	Webhook Back
→ ONBOARDING	user submits signup form	Verify	`POST /v2/accounts/{sid}/verifications/sms`	`status: approved` on verify check
→ ACTIVATED	user completes first key action	SMS / WhatsApp	Send welcome + activation confirmation	delivery callback `status: delivered`
→ ENGAGED	regular usage detected (your signal)	Campaigns	Tag user in active segment	—
→ AT_RISK	no login for N days (configurable)	Campaigns / Voicebot	Trigger drip or bot call	bot session end event
→ CHURNED	no response to AT_RISK interventions	—	Internal state update	—
→ OFFBOARDED	explicit delete / GDPR request	SMS	Confirmation SMS	delivery callback

Retry Logic and Fallback Channels

OTP via SMS
  └─ deliver? No → wait 30s → retry SMS (max 2x)
               No → fall back to Voice OTP call
                    └─ answered? No → mark verification_failed

WhatsApp template
  └─ delivered? No (30004–30041) → fall back to SMS transactional
               Seen but no response in T minutes → trigger Chatbot proactive message

Voicebot call
  └─ answered? No → retry after 2h (max 2x)
              Yes, but incomplete → escalate to SmartConnect agent

3. Product Integration Specs

3.1 Verify (OTP / 2FA)

Trigger: User submits phone number at signup, login, or sensitive action (payment, profile change).

Start Verification

POST https://exoverify.exotel.com/v2/accounts/{account_sid}/verifications/sms
Authorization: Basic <base64(app_id:app_secret)>
Content-Type: application/json

{
  "application_id": "your_exoverify_app_id",
  "phone_number": "+919876543210"
}

Response: { "sid": "VE...", "status": "pending" }

Check OTP

POST https://exoverify.exotel.com/v2/accounts/{account_sid}/verifications/sms/{verification_sid}/check
Authorization: Basic <base64(app_id:app_secret)>
Content-Type: application/json

{
  "otp": "482916"
}

Response: { "status": "approved" | "pending" | "failed" }

Webhook: No push webhook on verify — poll or use the check response directly.

Fallback: If SMS OTP times out (60s default), offer a "resend via voice call" option. Implement a separate voice call using the Voice API with a TTS message containing the OTP.

Integration notes:

OTP expiry: 60 seconds. Max attempts: 10 per verification SID.
One verification SID per phone number per session. Don't reuse SIDs.
Use replace_vars to inject custom parameters into the OTP template if your DLT template requires it.
Rate-limit your resend button client-side — Exotel allows up to 10 attempts but excessive OTP sends flag the account.

3.2 Voice (Outbound, Inbound IVR, SmartConnect, Click-to-Call)

Trigger: Activation nudge call, churn win-back call, support escalation, Click-to-Call from web/app.

Outbound call (Click-to-Call / agent-to-customer)

POST https://{api_key}:{api_token}@ccm-api.in.exotel.com/v2/accounts/{account_sid}/calls
Content-Type: application/json

{
  "from": { "user_id": "agent-uuid-from-dashboard" },
  "to": { "number": "+919876543210" },
  "virtual_number": "+911140XXXXXX",
  "recording": true,
  "recording_channels": "dual",
  "custom_field": "user_id:u_12345|ticket:TK_9900",
  "status_callback": [
    { "event": "terminal", "url": "https://api.yourapp.com/webhooks/exotel/call" }
  ]
}

Webhook payload (terminal event)

{
  "CallSid": "c4e6a...",
  "Status": "completed",
  "Duration": "183",
  "RecordingUrl": "https://storage.exotel.com/...",
  "custom_field": "user_id:u_12345|ticket:TK_9900"
}

Key fields: Status (completed, no-answer, busy, failed), Duration, RecordingUrl.

SmartConnect (inbound routing): Configure in the Exotel dashboard to map inbound ExoPhone to a queue or flow. Skills-based routing uses applet parameters. No direct API — configured via dashboard flow builder, with passthrough webhook on call-connect and call-end events.

Fallback: no-answer or busy → schedule retry in 2h (max 2 attempts). After 2 failures, escalate to Campaigns for async drip.

Integration notes:

custom_field (max 255 chars) is your primary correlation key between the Exotel call and your internal record. Store CallSid → your internal ID in Redis for sub-second webhook lookup.
recording_channels: "dual" required for CQA analysis (separate agent/customer tracks).
Voice v2 (CCM API) requires agents as co-workers in the dashboard. For system-initiated calls with no agent (e.g., outbound dialer, notifications), use Voice v1 (/v1/Accounts/{sid}/Calls/connect).

3.3 SMS

Trigger: Transactional alerts (OTP, order, status change), activation nudges, churn fallback messages.

Send transactional SMS

POST https://{api_key}:{api_token}@api.in.exotel.com/v1/Accounts/{account_sid}/Sms/send
Content-Type: application/x-www-form-urlencoded

From=EXOTEL&To=%2B919876543210&Body=Your+order+%23ORD-001+is+confirmed.&DltEntityId=1234567890123&DltTemplateId=9876543210987&StatusCallback=https%3A%2F%2Fapi.yourapp.com%2Fwebhooks%2Fexotel%2Fsms

Webhook payload

{
  "SmsSid": "SM...",
  "To": "+919876543210",
  "Status": "delivered",
  "ErrorCode": null,
  "DateSent": "2026-05-19T10:23:00Z"
}

Key Status values: sent, delivered, undelivered, failed.

Fallback: If Status: undelivered within 5 minutes, retry once. After two failures, fall back to WhatsApp template message.

Integration notes:

DLT compliance is mandatory for India. Every outbound SMS requires DltEntityId (your registered entity) and DltTemplateId (pre-approved template). Without these, messages will be blocked by carriers.
Promotional messages (SmsType=promotional) are restricted to 9am–9pm IST. Transactional messages (transactional) have no time restriction.
Bulk dynamic SMS: up to 100 unique messages per request. Use the bulk endpoint with an array payload.
Rate limit: 200 requests/min per account.

3.4 WhatsApp Business API

Trigger: Onboarding welcome, feature adoption nudges, support notifications, churn outreach (high engagement channel).

Send template message

POST https://{api_key}:{api_token}@api.in.exotel.com/v2/accounts/{account_sid}/messages
Content-Type: application/json

{
  "to": "+919876543210",
  "from": "whatsapp:+9191XXXXXXXX",
  "type": "template",
  "template": {
    "name": "onboarding_welcome_v2",
    "language": { "code": "en" },
    "components": [
      {
        "type": "body",
        "parameters": [
          { "type": "text", "text": "Priya" },
          { "type": "text", "text": "7 days" }
        ]
      }
    ]
  }
}

Send interactive message (buttons)

{
  "to": "+919876543210",
  "from": "whatsapp:+9191XXXXXXXX",
  "type": "interactive",
  "interactive": {
    "type": "button",
    "body": { "text": "Ready to activate your account?" },
    "action": {
      "buttons": [
        { "type": "reply", "reply": { "id": "activate_yes", "title": "Yes, activate" } },
        { "type": "reply", "reply": { "id": "activate_later", "title": "Remind me later" } }
      ]
    }
  }
}

Webhook (inbound message / delivery)

{
  "MessageSid": "WA...",
  "From": "whatsapp:+919876543210",
  "To": "whatsapp:+9191XXXXXXXX",
  "Body": "activate_yes",
  "ButtonPayload": "activate_yes",
  "Status": "delivered",
  "StatusCode": 30002
}

Inbound handling: Register an inbound webhook URL in the Exotel dashboard. Parse ButtonPayload for interactive replies; Body for free-text. Route to your Chatbot or backend based on content.

Fallback: On status codes 30004–30041 (failed), fall back to SMS transactional with same message content.

Integration notes:

All template messages require WhatsApp pre-approval. Template rejection (status: rejected) will return a 4xx. Build a retry queue with a 24h backoff for template re-approvals.
24-hour messaging window: after a user-initiated message, you can send free-form messages for 24 hours. Outside this window, only approved templates are allowed.
WhatsApp supports bulk up to 100 messages per API call.

3.5 Campaigns / Engage

Trigger: Lifecycle stage changes (AT_RISK detected, Day 7 inactivity, post-activation upsell window).

Integration pattern: Campaigns are configured in the Exotel Engage dashboard (segment builder + drip sequence). Your backend drives them via two methods:

Method A — Event-triggered via API Push a lifecycle event to the Campaigns API to enroll a user in a sequence:

POST https://{api_key}:{api_token}@api.in.exotel.com/v1/Accounts/{sid}/Campaigns/enroll
Content-Type: application/json

{
  "campaign_id": "CMP_onboarding_day7",
  "contacts": [
    {
      "phone": "+919876543210",
      "custom_fields": {
        "user_id": "u_12345",
        "last_login": "2026-05-12"
      }
    }
  ]
}

Method B — Segment sync Sync your user segments to Exotel Contacts via the Contacts API. Campaigns read from these segments on schedule.

Webhook on campaign event completion: Configure per-campaign webhooks to receive send/delivery/response events per user.

Fallback: Multi-channel drip sequences can be configured natively: Day 0 WhatsApp → Day 2 SMS → Day 5 Voice call. If a user responds on any channel, remove them from the sequence by calling the unenroll endpoint.

Integration notes:

Idempotency: enrolling the same phone + campaign_id twice does not create duplicates if the user is already active in the sequence.
For time-sensitive lifecycle events (AT_RISK detection), prefer Method A (event API) over segment sync to avoid lag.

3.6 Voicebot

Trigger: Activation nudge calls (Day 7), churn win-back calls, post-onboarding check-in, automated collections, NPS surveys.

How it works: The Voicebot is an AI-powered call handler. You trigger an outbound call using the Voice API with the bot's IVR flow as the call handler. The bot uses NLP + DTMF for input, calls your tools (via OpenAPI or Python functions in the Tools Server), and escalates to a live agent via SmartConnect when it can't resolve.

Trigger an outbound Voicebot call

POST https://{api_key}:{api_token}@api.in.exotel.com/v1/Accounts/{account_sid}/Calls/connect
Content-Type: application/x-www-form-urlencoded

From=+9191XXXXXXXX&To=%2B919876543210&Url=https%3A%2F%2Fmy.exotel.com%2F{account_sid}%2Fexoml%2Ffetch%2F{voicebot_flow_id}&CustomField=user_id%3Au_12345&StatusCallback=https%3A%2F%2Fapi.yourapp.com%2Fwebhooks%2Fexotel%2Fvoicebot

Url points to the VoiceBot ExoML flow. CustomField passes context the bot can read via its tools.

DTMF + NLP input handling:

DTMF: bot presents menu (Press 1 to confirm, 2 to speak to an agent). <Gather> node collects digit input.
NLP: free-speech input is transcribed and interpreted by the bot's configured LLM. Intents map to bot actions.

Escalation to live agent (SmartConnect): When the bot detects it cannot resolve (low-confidence NLP, explicit user request, N retries exhausted), it transfers the call:

<!-- VoiceBot ExoML escalation node -->
<Connect>
  <Queue>retention-agents</Queue>
</Connect>

Session context (user ID, bot interaction summary) is passed as custom_field to the agent leg, and can be surfaced in your CRM via the terminal webhook.

Webhook (session end)

{
  "CallSid": "CA...",
  "Status": "completed",
  "CustomField": "user_id:u_12345",
  "BotSessionId": "BS_abc123",
  "BotOutcome": "escalated_to_agent | resolved | unanswered"
}

Fallback: If the call is not answered, use the Campaign retry logic. If the bot session ends with unanswered 3x, escalate to human outreach queue.

Integration notes:

Tools registered in the Voicebot Tools Server (OpenAPI or Python) are invoked in real-time during the call. Ensure tool endpoints respond within 3s or the bot will time out.
The bot can read CustomField values if your tool fetches them via your API using the CallSid.
Pass recording: true on the call and record in dual-channel for CQA ingestion.

3.7 CQA (Conversation Quality Analytics)

Trigger: Post-call (triggered from Status: completed webhook), post-chat (triggered from chat session close event).

Ingest a call for analysis

POST https://cqa.exotel.com/cqa/api/v1/accounts/{account_id}/ingress/interactions
X-API-Key: {cqa_api_key}
Content-Type: application/json

{
  "external_interaction_id": "call-{CallSid}",
  "channel_type": "VOICE",
  "audio_url": "{RecordingUrl}",
  "audio_format": "WAV",
  "interaction_start_time": "2026-05-19T10:00:00Z",
  "duration_seconds": 183,
  "callback_url": "https://api.yourapp.com/webhooks/cqa",
  "metadata": {
    "user_id": "u_12345",
    "lifecycle_stage": "AT_RISK",
    "agent_id": "agent-42",
    "campaign": "churn-prevention-q2"
  }
}

CQA webhook (analysis complete)

{
  "event": "INTERACTION_ANALYSIS_COMPLETED",
  "externalInteractionId": "call-CA...",
  "data": {
    "analysisId": "a1b2c3d4-...",
    "finalScore": 72.5,
    "criticalityAdjustedScore": 68.0,
    "kpiResults": [
      {
        "kpiId": "kpi-101",
        "aiResponse": "No",
        "aiJustification": "Agent did not offer retention discount.",
        "finalScore": 0.0
      }
    ]
  }
}

What CQA returns:

finalScore / criticalityAdjustedScore — overall quality score (0–100)
Per-category scores (Communication, Compliance, Resolution)
Per-KPI aiResponse, aiJustification, aiSuggestion
Implicit: transcript (accessible via transcript_url after processing) and sentiment signal embedded in KPI justifications

Automated lifecycle decisions from CQA:

def handle_cqa_webhook(payload):
    score = payload["data"]["finalScore"]
    user_id = get_user_from_interaction(payload["externalInteractionId"])

    if score < 50:
        # Low quality interaction → re-trigger retention campaign
        enroll_in_campaign(user_id, "CMP_retention_followup")
    elif score < 70:
        # Moderate → flag for QA team review
        create_review_task(user_id, payload["data"]["analysisId"])
    else:
        # Good outcome → update lifecycle stage
        update_lifecycle_state(user_id, "ENGAGED")

Integration notes:

409 Conflict on duplicate external_interaction_id — use CallSid as the ID for deduplication.
CQA supports VOICE, CHAT, EMAIL, SMS, WHATSAPP channel types. Chatbot sessions can also be ingested.
Webhook delivery: 3 attempts (0s, 10s, 30s). Return 200 immediately; process async.
HMAC verification: X-CQA-Signature: sha256={hex} signed with your API key secret.

3.8 Chatbot

Trigger: Inbound web/WhatsApp message, proactive outreach initiated by your backend, support request.

Proactive session initiation (WhatsApp): Send a WhatsApp template message that includes a "Chat with us" CTA. When the user replies, the inbound webhook routes to the chatbot flow configured for that number.

Inbound webhook routing:

Inbound WhatsApp message
  → Exotel routes to configured Chatbot flow
  → Bot processes intent
  → Bot calls your API via Actions node (if CRM lookup needed)
  → Bot responds

If bot cannot resolve:
  → Bot transfers to LiveChat queue (SmartConnect)
  → Agent picks up the session

Chatbot → Voicebot handoff: If the user explicitly requests a voice call or the bot determines the issue needs voice, trigger a Voicebot call:

Chatbot captures user consent (Reply YES to receive a call)
On user consent, chatbot webhook fires to your backend
Your backend calls the Voice API to initiate a Voicebot call, passing session context via CustomField
Voicebot picks up with context (user name, issue summary) pre-loaded from your CRM

Session context passing:

// Passed as CustomField on the Voice API call
{
  "chat_session_id": "CS_abc123",
  "user_id": "u_12345",
  "issue_summary": "Cannot upgrade plan",
  "bot_resolution_attempts": 2
}

LiveChat escalation webhook: When the chatbot transfers to an agent, Exotel fires a session-handoff event:

{
  "event": "live_chat_assigned",
  "session_id": "CS_abc123",
  "agent_id": "agent-42",
  "transcript_url": "https://...",
  "user_id": "u_12345"
}

Fallback: If no agent is available in the LiveChat queue (beyond SLA threshold), bot sends a callback scheduling message and creates a ticket in your system.

Integration notes:

Chatbot flows are built in the visual Flow Builder. For dynamic data (user plan, balance), use the API Action node pointing to your backend.
WhatsApp chatbot sessions are scoped to the 24-hour messaging window. Outside the window, the bot cannot initiate free-form messages — it must use a template first.
Bot analytics (session count, completion rate, drop-off nodes) are available via the Analytics dashboard and the Download Reports API.

4. Key Flows

4.1 Onboarding Flow

User          Your Backend       Exotel Verify     WhatsApp API      Chatbot
 |                 |                   |                 |               |
 |--POST /signup-->|                   |                 |               |
 |                 |--POST /verifications/sms {phone}--->|               |
 |<----SMS OTP-----|-------------------|                 |               |
 |--POST /verify-->|                   |                 |               |
 |                 |--POST /verifications/{sid}/check--->|               |
 |                 |<--{status:"approved"}---------------|               |
 |                 |--create_user(), state=ONBOARDING    |               |
 |                 |                                     |               |
 |                 |--POST /messages (onboarding_welcome_template)------>|
 |<--WA welcome msg with [Start Setup] button-----------|               |
 |--[Start Setup] reply------------------------>|                        |
 |                 |<--inbound webhook {ButtonPayload:"start_setup"}     |
 |                 |--route to onboarding_flow-------------------------->|
 |<--Chatbot-guided setup (profile, preferences)------------------------|
 |                 |                                                      |
 |  [if stuck / no response 10min]                                       |
 |                 |<--session_stalled webhook---------------------------|
 |                 |--POST /messages (offer agent)--------------->|      |
 |--"Talk to someone"-------------------------------------->|             |
 |                 |--SmartConnect queue: onboarding-agents              |
 |                 |                                                      |
 |                 |<--setup_complete webhook----------------------------|
 |                 |--state=ACTIVATED                                    |

4.2 Activation Nudge Flow (Day 7 Inactivity)

Your Backend      Campaigns        WhatsApp API      SMS API       Voicebot    SmartConnect
     |                |                  |               |              |             |
     |--cron: inactive >= 7d, state=ONBOARDING          |              |             |
     |--POST /campaigns/enroll {campaign:"activation_d7"}|             |             |
     |                |--Day 0: WhatsApp template------->|             |             |
     |<--delivery webhook--------------------|            |             |             |
     |                |                      |            |             |             |
     |  [no response in 48h]                 |            |             |             |
     |                |--Day 2: SMS nudge--------------->|             |             |
     |<--delivery webhook----------------------------------|            |             |
     |                |                                   |             |             |
     |  [no response in 96h]                              |             |             |
     |--POST /Calls/connect (voicebot_activation_flow)--->|            |             |
     |<--call answered------------------------------------|             |             |
     |                |                                                 |             |
     |  [user engages with bot]                                         |             |
     |<--BotOutcome:"activated"-----------------------------------------|            |
     |--state=ACTIVATED                                                 |             |
     |                |                                                 |             |
     |  [bot cannot resolve]                                            |             |
     |                |                    Transfer to retention agent->|------------>|
     |<--call_end webhook {Duration, RecordingUrl}---------------------|-------------|
     |--POST /ingress/interactions {audio_url, metadata}               |             |
     |                |                                                 |             |
     |  [no-answer x2 after voicebot]                                  |             |
     |--state=AT_RISK, schedule churn_prevention flow                  |             |

4.3 Churn Prevention Flow

Your Backend      Chatbot          User           Voicebot     SmartConnect     CQA
     |                |              |                |              |            |
     |--at_risk signal detected (usage drop, billing flag)          |            |
     |--state=AT_RISK                |                |              |            |
     |                |              |                |              |            |
     |--trigger proactive WA chatbot session          |              |            |
     |                |--"We noticed you haven't been active..."---->|            |
     |                |              |                |              |            |
     |  [user responds]              |                |              |            |
     |<--session outcome: resolved | escalate---------|             |            |
     |                |              |                |              |            |
     |  [no response in 24h]         |                |              |            |
     |--POST /Calls/connect (win_back_flow)---------->|             |            |
     |                |              |<--AI voice call with offer---|            |
     |<--{BotOutcome: offer_accepted|declined|escalated}------------|            |
     |                |              |                |              |            |
     |  [BotOutcome = escalated]     |                |              |            |
     |                |              |  Transfer to retention spec.->|            |
     |<--call_end {CallSid, RecordingUrl, Duration}----------------|            |
     |--POST /ingress/interactions {audio_url, stage:"AT_RISK"}---->|            |
     |<--INTERACTION_ANALYSIS_COMPLETED webhook--------------------|------------|
     |                |              |                |              |            |
     |  finalScore < 60  → re-enroll in CMP_retention_followup     |            |
     |  offer_accepted   → state=ENGAGED                            |            |
     |  declined         → state=CHURNED                            |            |

4.4 Support Escalation Flow

User         Chatbot      Your Backend     Voicebot     Agent (SC)      CQA
  |              |               |              |             |           |
  |--inbound msg (web/WA)------->|              |             |           |
  |              |--intent classification + response attempt  |           |
  |<--bot response---------------|              |             |           |
  |              |               |              |             |           |
  |  [bot cannot resolve]        |              |             |           |
  |<--"Let me connect you to voice"-------------|            |           |
  |              |--handoff webhook {session_id, summary}---->|          |
  |              |               |--POST /Calls/connect------>|          |
  |<--outbound call (AI voice support)----------|             |           |
  |              |               |              |             |           |
  |  [voicebot cannot resolve]   |              |             |           |
  |              |               |  Connect <Queue>support-tier1>-------->|
  |              |               |<--call_answered {CallSid, AgentId}----|
  |<--live call with agent------------------------------------------------|
  |              |               |              |             |           |
  |              |               |<--call_end {CallSid, RecordingUrl}----|
  |              |               |--POST /ingress/interactions {audio_url,
  |              |               |   channel_type:VOICE, metadata:       |
  |              |               |   {agent_id, ticket_id, session_id}}->|
  |              |               |<--INTERACTION_ANALYSIS_COMPLETED-------|
  |              |               |   {finalScore, kpiResults}            |
  |              |               |                                        |
  |              |  finalScore < 60  → flag for QA review                |
  |              |  FCR KPI = No     → schedule callback                 |

5. CQA Integration Detail

Where CQA plugs in

Touchpoint	Integration	Trigger
Post-voice-call	REST ingest	`Status: completed` webhook from Voice API
Post-voicebot-call	REST ingest	`BotOutcome` webhook from Voicebot session
Post-live-chat	REST ingest	Session close event from Chatbot LiveChat
Real-time coaching	CQA dashboard (not API)	Not available via API at present

Data returned by CQA analysis

{
  "finalScore": 72.5,
  "criticalityAdjustedScore": 68.0,
  "categories": [
    {
      "name": "Communication Skills",
      "finalScore": 80.0,
      "sub_categories": [...]
    },
    {
      "name": "Compliance",
      "finalScore": 55.0,
      "sub_categories": [...]
    }
  ],
  "kpiResults": [
    {
      "kpiId": "kpi-201",
      "aiResponse": "No",
      "aiJustification": "Agent did not confirm resolution before closing.",
      "finalScore": 0.0
    }
  ]
}

Transcripts are available by fetching the interaction detail after status = completed.

Automated lifecycle decisions from CQA

CQA_SCORE_THRESHOLDS = {
    "trigger_retention_campaign": 50,
    "flag_for_qa_review": 70,
    "auto_close_resolved": 85,
}

def process_cqa_result(interaction_id, final_score, kpi_results, metadata):
    user_id = metadata["user_id"]

    # Check for critical KPI failures
    critical_fails = [k for k in kpi_results if k["finalScore"] == 0.0 and k.get("is_critical")]

    if critical_fails:
        create_compliance_alert(agent_id=metadata["agent_id"], kpis=critical_fails)

    if final_score < CQA_SCORE_THRESHOLDS["trigger_retention_campaign"]:
        enroll_campaign(user_id, "CMP_post_call_recovery")
    elif final_score < CQA_SCORE_THRESHOLDS["flag_for_qa_review"]:
        create_qa_task(interaction_id)
    else:
        auto_close_ticket(metadata.get("ticket_id"))
        if metadata.get("lifecycle_stage") == "AT_RISK":
            update_lifecycle_state(user_id, "ENGAGED")

6. Voicebot + Chatbot Handoff

Channel switching: Chat → Voice

Chatbot session (WhatsApp)
  │
  ├─ Issue unresolvable by bot
  │
  ▼
Bot sends: "Would you like us to call you? Reply YES"
User: "YES"
  │
  ▼
Chatbot webhook → your backend
  │
  ▼
Voice API: POST /Calls/connect
  CustomField = {
    "chat_session_id": "CS_abc",
    "user_id": "u_12345",
    "bot_intent": "billing_dispute",
    "prior_steps": ["confirmed_account", "checked_invoice"]
  }
  │
  ▼
Voicebot call starts
Voicebot tool (OpenAPI) fetches context via GET /sessions/{chat_session_id}
Bot continues conversation with full context

Unified conversation history

Maintain a conversations table in your DB:

conversations (
  id           UUID PRIMARY KEY,
  user_id      UUID NOT NULL,
  channel      ENUM('whatsapp', 'web', 'voice', 'voicebot'),
  session_id   TEXT,          -- chatbot session ID or CallSid
  started_at   TIMESTAMPTZ,
  ended_at     TIMESTAMPTZ,
  transcript   JSONB,         -- raw turn-by-turn, stored after session ends
  cqa_score    FLOAT,         -- populated after CQA analysis completes
  outcome      TEXT,          -- resolved / escalated / unanswered / transferred
  parent_id    UUID           -- links voice leg back to originating chat session
)

When the Voicebot escalates to SmartConnect, the agent receives the call with CustomField containing chat_session_id. Surface this in your agent UI by fetching the chatbot transcript via GET /conversations?session_id=CS_abc.

Both bots escalating to live agents (SmartConnect)

Chatbot → LiveChat: Configure a "Transfer to Agent" node in the Chatbot Flow Builder. Set the target queue name. Chatbot fires a live_chat_assigned webhook to your backend.

Voicebot → SmartConnect: The Voicebot ExoML flow uses <Connect><Queue>queue-name</Queue></Connect>. On queue connect, the SmartConnect call-connect webhook fires to your backend.

Both paths should carry the user_id and session context so your agent desktop can surface the right record without the agent asking for account details again.

7. Data & State Management

Lifecycle state model (your DB)

users (
  id                  UUID PRIMARY KEY,
  phone               TEXT UNIQUE NOT NULL,
  lifecycle_stage     ENUM('ACQUIRED','ONBOARDING','ACTIVATED','ENGAGED','AT_RISK','CHURNED','OFFBOARDED'),
  stage_updated_at    TIMESTAMPTZ,
  last_contact_at     TIMESTAMPTZ,
  last_contact_channel TEXT,          -- 'sms' | 'whatsapp' | 'voice' | 'voicebot' | 'chatbot'
  channel_preference  TEXT,           -- preferred channel, updated from engagement data
  verify_sid          TEXT,           -- active verification SID
  active_campaign_id  TEXT,
  cqa_last_score      FLOAT,
  opt_out_sms         BOOLEAN DEFAULT false,
  opt_out_whatsapp    BOOLEAN DEFAULT false,
  created_at          TIMESTAMPTZ
)

Keeping state in sync from webhooks

Each Exotel webhook event maps to a state update:

Webhook	State Action
Verify `status: approved`	`lifecycle_stage → ONBOARDING`, `last_contact_channel = 'sms'`
WhatsApp `status: delivered`	`last_contact_at = now()`
WhatsApp inbound reply	`last_contact_at = now()`, `channel_preference = 'whatsapp'`
Voice `Status: completed` with duration > 30s	`last_contact_at = now()`
Voicebot `BotOutcome: resolved`	depends on flow — map outcome → stage
Chatbot session close with `resolved: true`	`last_contact_at = now()`
CQA `finalScore < 50`	trigger retention campaign, potentially `stage → AT_RISK`

Idempotency and duplicate webhook delivery

Exotel and CQA may re-deliver webhooks on timeout (see §3.7 retry policy). Deduplicate using a processed_events table:

processed_events (
  event_id    TEXT PRIMARY KEY,  -- CallSid, SmsSid, WA MessageSid, CQA deliveryId
  event_type  TEXT,
  processed_at TIMESTAMPTZ
)

Before processing any webhook:

def handle_webhook(event_id, event_type, payload):
    if db.exists("processed_events", event_id):
        return 200  # already handled
    db.insert("processed_events", event_id, event_type)
    process(payload)

Use a Redis SET with TTL (7 days) for high-throughput event deduplication instead of a DB write.

8. Error Handling & Observability

Failure modes per product

Product	Failure Mode	Detection	Recovery
Verify	OTP not delivered	`status: pending` after 60s	Retry SMS x2 → fall back to voice OTP
Verify	Invalid OTP	`status: failed` on check	Allow up to 3 user retries, then invalidate SID
SMS	Undelivered	webhook `Status: undelivered`	Retry x1 → fall back to WhatsApp
SMS	DLT rejection	4xx on API call (`DLT_TEMPLATE_NOT_FOUND`)	Fix template mapping; do not retry until resolved
WhatsApp	Template rejected	`StatusCode: 30004+`	Fall back to SMS; audit template compliance
WhatsApp	24h window expired	4xx `HSM_MESSAGE_ONLY`	Send approved template to reopen session
Voice	No answer	`Status: no-answer`	Retry in 2h (max 2x) → fall back to async channel
Voicebot	Tool timeout (>3s)	Bot session ends with `error`	Implement tool fallback response; log for investigation
Voicebot	No agent in queue	Queue timeout callback	Offer callback scheduling in bot
CQA	Analysis failed	`INTERACTION_ANALYSIS_FAILED` webhook	Re-ingest with same `external_interaction_id` — 409 means already queued, which means retry
Chatbot	API action timeout	Bot flow error node	Bot sends fallback message; creates support ticket

Key metrics to monitor

Metric	Source	Alert Threshold
OTP delivery rate	Verify — `status: approved` / total starts	< 85% delivery
SMS delivery rate	SMS webhook `delivered` / `sent`	< 90%
WhatsApp delivery rate	WA webhook `StatusCode: 30002` / total sent	< 85%
Voice connect rate	Voice webhook `Status: completed` / total calls	< 60%
Voicebot completion rate	`BotOutcome: resolved` / total bot calls	< 40% (tune flow)
Chatbot session resolution	resolved sessions / total sessions	< 50%
CQA processing failure rate	`INTERACTION_ANALYSIS_FAILED` / total ingested	> 2%
CQA average score by stage	CQA webhook `finalScore` grouped by lifecycle stage	Score < 60 for AT_RISK calls

Recommended alerting setup

P1 (immediate): DLT rejection rate > 1% (upstream config issue); Verify OTP delivery < 70% (carrier issue)
P2 (15 min): Voice connect rate < 50% over 1h window; CQA failure rate > 5%
P3 (daily digest): Voicebot completion rate trending down week-over-week; Chatbot escalation rate > 30%

Instrument your webhook handler with structured logs keyed on CallSid / SmsSid / MessageSid. These IDs are the join key between Exotel events and your internal records. Store them in your conversations and users tables from the first event.

1. System Architecture​

Component Overview​

Where Exotel Sits in Your Stack​

Webhook Event Bus Pattern​

2. Lifecycle State Machine​

States​

State Transition Table​

Retry Logic and Fallback Channels​

3. Product Integration Specs​

3.1 Verify (OTP / 2FA)​

3.2 Voice (Outbound, Inbound IVR, SmartConnect, Click-to-Call)​

3.3 SMS​

3.4 WhatsApp Business API​

3.5 Campaigns / Engage​

3.6 Voicebot​

3.7 CQA (Conversation Quality Analytics)​

3.8 Chatbot​

4. Key Flows​

4.1 Onboarding Flow​

4.2 Activation Nudge Flow (Day 7 Inactivity)​

4.3 Churn Prevention Flow​

4.4 Support Escalation Flow​

5. CQA Integration Detail​

Where CQA plugs in​

Data returned by CQA analysis​

Automated lifecycle decisions from CQA​

6. Voicebot + Chatbot Handoff​

Channel switching: Chat → Voice​

Unified conversation history​

Both bots escalating to live agents (SmartConnect)​

7. Data & State Management​

Lifecycle state model (your DB)​

Keeping state in sync from webhooks​

Idempotency and duplicate webhook delivery​

8. Error Handling & Observability​

Failure modes per product​

Key metrics to monitor​

Recommended alerting setup​

1. System Architecture

Component Overview

Where Exotel Sits in Your Stack

Webhook Event Bus Pattern

2. Lifecycle State Machine

States

State Transition Table

Retry Logic and Fallback Channels

3. Product Integration Specs

3.1 Verify (OTP / 2FA)

3.2 Voice (Outbound, Inbound IVR, SmartConnect, Click-to-Call)

3.3 SMS

3.4 WhatsApp Business API

3.5 Campaigns / Engage

3.6 Voicebot

3.7 CQA (Conversation Quality Analytics)

3.8 Chatbot

4. Key Flows

4.1 Onboarding Flow

4.2 Activation Nudge Flow (Day 7 Inactivity)

4.3 Churn Prevention Flow

4.4 Support Escalation Flow

5. CQA Integration Detail

Where CQA plugs in

Data returned by CQA analysis

Automated lifecycle decisions from CQA

6. Voicebot + Chatbot Handoff

Channel switching: Chat → Voice

Unified conversation history

Both bots escalating to live agents (SmartConnect)

7. Data & State Management

Lifecycle state model (your DB)

Keeping state in sync from webhooks

Idempotency and duplicate webhook delivery

8. Error Handling & Observability

Failure modes per product

Key metrics to monitor

Recommended alerting setup