Generic webhook delivery#

Configure any absolute HTTP(S) endpoint with POST /webhooks. Remind does not require, discover, or contact any provider-specific service. In production, endpoints must use HTTPS; credentials and URL fragments are rejected. The endpoint may use any host, path, and query string. A signing secret is optional.

A Silicon may have zero, one, or many active subscriptions. GET /webhooks lists them and DELETE /webhooks/{subscription_id} disables one. The legacy PUT /webhook and DELETE /webhook routes remain as compatibility aliases.

Request contract#

The worker posts UTF-8 JSON:

{
  "type": "remind.schedule.triggered",
  "source": "silicon-remind",
  "subject": "<schedule-uuid>",
  "occurred_at": "<intended-UTC-trigger>",
  "schema_version": "1.0",
  "payload": {
    "execution_id": "<stable-occurrence-uuid>",
    "schedule_id": "<schedule-uuid>",
    "silicon_id": "handle:org",
    "text": "<exact reminder text>",
    "scheduled_for": "<intended-UTC-trigger>",
    "timezone": "Asia/Kolkata"
  }
}

webhook-id and Idempotency-Key contain the execution UUID. When a signing secret is configured, webhook-timestamp contains the attempt's Unix seconds and webhook-signature is v1, plus standard padded base64 HMAC-SHA256 over <webhook-id>.<webhook-timestamp>.<exact JSON bytes>. Unsigned destinations receive no signature headers.

Any HTTP 2xx response, with any response body including an empty body, marks the attempt delivered. Remind stores the execution UUID as its local receipt marker; there is no provider-specific receipt format.

Retries and duplicates#

Transport errors, 408, 425, 429, and all 5xx responses retry with bounded exponential backoff and jitter. Other 3xx/4xx responses terminate the occurrence. Redirects are disabled and response bodies are size bounded.

Delivery is at least once across uncertain network outcomes. Consumers should deduplicate using payload.execution_id. The scheduler's unique occurrence constraint prevents multiple logical executions for one schedule/version/trigger; it cannot create exactly-once network delivery.