Runs on your device
API Workbench
JWT decoder, timestamps, webhook signatures, a regex tester with plain-language explanations and cURL → fetch / Python / Dart — on your device.
Never paste production tokens that are still valid into any website — including this one.
About this tool
The API tester opens on its own page, because it may call any address.
Our tools run in your browser — nothing you paste or open is uploaded to us or stored by us. We only count how often each tool is opened, never what you enter. The API tester is a separate page so a token pasted into JWT never sits on a page that can send data anywhere.