generated: '2026-10-03'
method: searched
generator: extract-docs-artifacts.py (local)
source: https://developers.sinch.com/docs/conversation/callbacks/webhook-routing.md
sources:
- https://developers.sinch.com/docs/conversation/callbacks/webhook-routing.md
- https://developers.sinch.com/docs/voice/tutorials/getting-a-second-number-and-testing-sinch-callbackswebhooks-with-ngrok.md
- https://developers.sinch.com/docs/voice-2.0/api-reference/webhook-signature.md
- https://developers.sinch.com/docs/conversation/callbacks.md
description: Sinch provides webhooks for multiple products. The Conversation API uses a set of trigger names (e.g., MESSAGE_INBOUND) while the
  Voice API uses event names such as call.incoming, call.answered, call.hangup, etc.
events:
- event: call.incoming
  description: Delivered when an inbound call is received.
- event: call.answered
  description: Delivered when a call is answered.
- event: call.hangup
  description: Delivered when a call ends.
- event: call.webhook.call.answered
  description: Example event name shown in the Voice webhook signature documentation.
- event: MESSAGE_INBOUND
  description: Inbound contact messages from end users on the underlying channels.
- event: MESSAGE_DELIVERY
  description: Delivery receipts for app messages sent on Conversation API channels.
- event: EVENT_INBOUND
  description: Inbound events (e.g., composing events) from end users.
- event: MESSAGE_SUBMIT
  description: Message submission notifications for app messages.
- event: EVENT_DELIVERY
  description: Delivery receipts for events sent on Conversation API channels.
- event: CONVERSATION_START
  description: Conversation start events.
- event: CONVERSATION_STOP
  description: Conversation stop events.
- event: CONVERSATION_DELETE
  description: Conversation deleted events.
- event: CONTACT_CREATE
  description: Contact create events.
- event: CONTACT_DELETE
  description: Contact delete events.
- event: CONTACT_MERGE
  description: Contact merge events.
- event: CONTACT_UPDATE
  description: Contact update events.
- event: CAPABILITY
  description: Results of asynchronous capability checks.
- event: OPT_IN
  description: Opt‑in events.
- event: OPT_OUT
  description: Opt‑out events.
- event: CONTACT_IDENTITIES_DUPLICATION
  description: Notifications about contact identity duplications.
- event: CHANNEL_EVENT
  description: Channel event notifications.
- event: RECORD_NOTIFICATION
  description: Record notifications.
- event: BATCH_STATUS_UPDATE
  description: Batch status update notifications.
- event: UNSUPPORTED
  description: Channel callbacks that are not natively supported by the Conversation API.
- event: SMART_CONVERSATION
  description: Machine‑learning analysis results for inbound messages.
- event: MESSAGE_INBOUND_SMART_CONVERSATION_REDACTION
  description: Inbound messages with content redacted based on analysis.
delivery:
  signature: Callbacks are signed using HMAC‑SHA256. The signature is placed in the `authorization` header as `service <serviceKey>:<Signature>`
    where the key/secret are taken from the Sinch dashboard. The request must also include an `x‑timestamp` header (ISO‑8601 UTC) which is part
    of the signed string.
  retries: The Conversation API uses exponential backoff retries. Retries occur when the response is not in the 200–299 range, specifically on
    network/timeout failures, OAuth2 token fetch failures, HTTP 5xx, and 429 status codes. Retries are not performed for other 4xx responses.
    The exact backoff schedule is not published.
docs: https://developers.sinch.com/docs/conversation/callbacks/webhook-routing.md