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Overview

EESI AI uses webhooks to communicate with telephony providers for call events and audio streaming. For outbound calls, EESI builds these URLs and hands them to the provider when it dials — you never configure them by hand. For inbound calls, you point your provider at a single dispatcher URL; see Inbound Calls. Every webhook path lives under /v1/telephony.

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Webhook Types

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1. Answer Webhook

When an outbound call connects, the provider requests instructions. The path is provider-specific, and EESI appends the routing parameters as a query string:
Telnyx and Asterisk ARI have no answer webhook. Telnyx is call-control style — EESI POSTs the stream and event URLs to Telnyx’s API instead of returning markup. ARI streams over a WebSocket only.
Here 123 is the workflow, 11 the organization, and 789 the workflow run.

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2. Status Callbacks

Receive call lifecycle events. Each is keyed on the workflow run: Providers report their own vocabulary; EESI normalizes it into a common set of states:
  • initiated - Call request received
  • ringing - Call is ringing
  • in-progress - Call is connected and streaming
  • answered - Call was answered
  • completed - Call ended normally
  • busy - Line was busy
  • no-answer - Call not answered
  • canceled - Call was canceled before connecting
  • failed - Call failed
  • error - Provider reported an error
A status EESI does not recognize is passed through unchanged rather than dropped.

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3. WebSocket Audio Stream

Real-time audio streaming for voice interaction. Endpoint: /v1/telephony/ws/{workflow_id}/{organization_id}/{workflow_run_id} Asterisk ARI instead connects to /v1/telephony/ws/ari and passes the same three values as query parameters — see Asterisk ARI. The organization_id segment is the tenant that owns the workflow. EESI scopes every workflow and workflow-run lookup by it, so a run belonging to one organization can never be served under another’s id. Audio Formats:
  • Twilio / Plivo / Vobiz: 8kHz μ-law (MULAW), Base64-encoded in JSON messages
  • Vonage: 16kHz Linear PCM, Binary frames
  • Asterisk ARI: 8kHz Linear PCM via externalMedia

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How It Works

EESI AI automatically:
  1. Constructs webhook URLs based on your deployment
  2. Passes them to the telephony provider when initiating calls
  3. Verifies webhook signatures for security:
    • Twilio: HMAC-SHA1 signature validation
    • Plivo / Vobiz: HMAC-SHA256 signature validation
    • Vonage: JWT token verification
  4. Processes status updates to track call lifecycle
  5. Manages WebSocket connections for audio streaming
  6. Handles provider-specific audio formats and protocols
Signature verification is implemented per provider in verify_inbound_signature. If you are adding a provider, see Custom Telephony Provider.

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Local Development

For local development, use the built-in Cloudflare tunnel:
The tunnel URL is automatically detected and used for webhooks.

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Troubleshooting

  • Verify your domain/tunnel URL is publicly accessible
  • Check firewall rules allow incoming HTTPS traffic
  • Test with curl from external network
  • Providers sign the full URL, query string included — a proxy that rewrites or reorders query parameters will invalidate the signature
  • Confirm the backend’s public URL matches what the provider was given, including scheme and port
  • Check WebSocket upgrade headers are preserved
  • Verify no timeout on load balancer/proxy
  • Monitor for memory/CPU constraints
  • Verify workflow_run_id is included in URL
  • Check provider console for webhook errors
  • Review webhook retry logs