Webhook deliveries failing

A failing webhook subscription presents in one of three ways: the delivery log shows non-2xx responses from the receiver, the log shows network errors before the receiver was reached, or the log is empty when the operator expected events.

Step 1: read the delivery log

Open Webhooks, the subscription in question, then Delivery log. Each entry shows:

• event_type and event_id.
• attempted_at.
• response_status (or a network-level error string).
• response_body (truncated).

If the log is empty, the events the subscription is bound to have not fired since the subscription was created. Trigger a test event by changing a metric's threshold to flip status, or wait for an organic event.

Step 2: non-2xx from the receiver

The delivery worker retries non-2xx responses. If retries exhaust, the entry moves to the Dead letter view; manual replay is available there.

Step 3: network errors

If response_status is missing and the log shows a network-level error:

Step 4: signature verification on the receiver

If the receiver computes a signature mismatch but the URL and secret are correct:

• Confirm the secret is the value Observer's webhook subscription page shows, not a copy with whitespace.
• Confirm the receiver computes HMAC-SHA-256(secret, raw_body) and compares against the X-Observer-Signature header value (after the sha256= prefix).
• Confirm the receiver hashes the raw request body, not a re-serialised JSON. Some web frameworks parse and re-serialise request bodies on the way to the handler; the recomputed signature does not match.

Step 5: subscription is disabled

A subscription whose enabled flag is off does not deliver events. The subscription edit page exposes the toggle. If a subscription was disabled while debugging, re-enable it to resume deliveries; new events fire from the moment it is re-enabled, not backfilled.