generated: '2026-07-18'
method: searched
source: https://docs.trychert.com/api/webhook-subscriptions
spec_type: Webhooks
docs:
  webhook_subscriptions: https://docs.trychert.com/api/webhook-subscriptions
  receiving_replies: https://docs.trychert.com/api/receiving-replies
  events: https://docs.trychert.com/api/events
transport:
  delivery: HTTP POST to subscriber URL
  streaming: SSE (server-sent events) available; polling and replay supported
events:
- name: message.received
  description: Recommended real-time inbound reply event; inbound images/files arrive as media parts
- name: lead_reply
  description: Legacy summary-style reply notification (still available)
- name: reaction.added
  description: A tapback reaction was added
- name: reaction.removed
  description: A tapback reaction was removed
subscription_operations:
- {op: create, method: POST, path: /api/v1/webhook-subscriptions, note: auto-generates a per-subscription secret}
- {op: list, method: GET, path: /api/v1/webhook-subscriptions, note: secret excluded}
- {op: retrieve, method: GET, path: "/api/v1/webhook-subscriptions/{id}"}
- {op: update, method: PATCH, path: "/api/v1/webhook-subscriptions/{id}", note: modify url, events, version, or active status}
- {op: delete, method: DELETE, path: "/api/v1/webhook-subscriptions/{id}"}
event_filtering:
  field: events
  semantics: exact-string match; omit events or send [] to subscribe to all events
signature_verification:
  algorithm: HMAC-SHA256
  signing_string: "<unix_ts>.<raw_body>"
  secret: per-subscription secret (shown once at creation)
  headers:
  - name: x-webhook-signature
    format: "v1,<timestamp>,<hex>"
    note: legacy
  - name: x-webhook-signature
    format: "t=<timestamp>,v1=<hex>"
    note: modern
  window_seconds: 300
  implementation_notes:
  - capture raw bytes before JSON parsing
  - verify against exact transmitted body
delivery_behavior:
  '2xx': marked delivered
  '4xx': not retried
  '5xx_or_unreachable': up to 3 attempts with exponential backoff
  dev_target: 'https://dev-inbox stored locally without an outbound POST'
  multiple_subscriptions: each receives independent delivery attempts
replay:
  op: POST /api/v1/events/{id}/replay
  target_one: add ?subscription_id=... to target a single subscription