Signature verification and security
How X-RR-Signature is computed, verification code for Node.js, Python and C#, guarding against replays, and how to replace a webhook secret.
Designing resends, ordering, and idempotency
What counts as success, the retry rules (1 min, 10 min, 1 h, four attempts), ordering and lost events, and dropping duplicates by X-RR-Delivery.
Webhook overview
Which webhook events are actually sent, what the request and signature headers look like, how duplicates, order and lost events behave, and when to use the API.
How to register a Webhook
Register a webhook in the developer portal or through the API, choose events that are actually sent, run a test send, and change, pause or delete a webhook.
Monitoring and handling failures
Read a webhook's active flag, last delivery time and delivery log, notice when it has switched itself off, recover, and fill the gap from the API.
SNS Webhook bypass (forwarding Webhooks from external SNS such as LINE)
Explains the mechanism, setup, signature handling, and cautions of the "SNS Webhook bypass" feature, which forwards Webhooks ReceiptRoller receives from SNS platforms such as LINE to a developer app, with the store's consent.