Webhook Tester

Webhooks are HTTP callbacks that services use to notify your application of events in real-time — payment completed, pull request opened, message received, form submitted. Unlike polling (repeatedly checking an API for changes), webhooks push notifications to your endpoint immediately when events occur. Testing webhooks presents a unique challenge: you need a publicly accessible URL to receive the webhook, the sending service must be configured to deliver to that URL, and you need to inspect the received payload to verify your handler processes it correctly. The AllTools Webhook Tester helps with the inspection step — when you receive a webhook payload (captured from logs, copied from documentation, or forwarded from a testing proxy), you can paste it into the tool to analyze the HTTP headers, request body structure, and data content. The tool formats JSON payloads for readability, highlights important fields like event types and signatures, and helps you understand the webhook structure before writing handler code. All analysis runs in your browser — webhook payloads often contain sensitive data like user information, payment details, or API credentials that should not be shared with external inspection services.

Building reliable webhook handlers requires attention to several critical practices. Always verify webhook signatures — services like Stripe, GitHub, Shopify, and Twilio sign payloads with HMAC using a shared secret so you can confirm the webhook genuinely came from the expected service and was not tampered with in transit. Use the AllTools HMAC Generator to compute expected signatures during development. Respond quickly with a 200 status code — webhook senders typically have short timeouts (5-30 seconds) and will retry on timeout or error responses, so acknowledge receipt immediately and process the payload asynchronously. Implement idempotent handlers — webhook retries mean your handler may receive the same event multiple times, so use event IDs to detect and skip duplicates. Log all received webhooks for debugging — when a handler fails, having the original payload available for replay is invaluable. Handle different event types with a router pattern — webhook endpoints typically receive multiple event types (payment.succeeded, payment.failed, subscription.created) and should dispatch to specific handlers based on the event type field.