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Tools / Webhook payload tester & mock sender

Webhook payload tester & mock sender

Test and debug webhooks from GitHub, Stripe, Slack, and Shopify. Compute HMAC-SHA256 signatures, dispatch mock payloads to endpoints with live latency measurement, and generate cURL commands.

Runs entirely in your browser

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About this tool

Webhooks let one service notify another with an HTTP request, but debugging them is awkward because you have to reproduce the sender. This tool helps on both sides: it can compute HMAC-SHA256 signatures (the way GitHub, Stripe, Slack and Shopify sign their payloads) so you can verify your validation logic, and it can dispatch mock payloads to your endpoint with live latency measurement, plus generate a matching cURL command.

That covers the two hard parts of webhook work — confirming that your signature verification is correct, and sending realistic test events without waiting for the real provider to trigger one. Getting the signature computation right is especially valuable, since a mismatch silently rejects legitimate webhooks.

It runs in your browser. Use it to build and debug a webhook receiver, verify HMAC signatures, or send test events to a staging endpoint.

Frequently asked questions

What does the webhook tester do?
It computes HMAC-SHA256 signatures like those from GitHub, Stripe, Slack and Shopify, and sends mock payloads to your endpoint with latency measurement, plus a cURL command.
Why is HMAC signature testing useful?
Providers sign webhook payloads so you can verify authenticity. Getting the signature computation wrong rejects real webhooks, so being able to reproduce and check it is valuable.
Can I send a test event to my own endpoint?
Yes. It dispatches mock payloads to a URL you specify and measures the response latency.
Is it done in the browser?
Yes. The signature computation and payload construction run in your browser.

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