Encoding and decoding are everywhere in web development: Base64 in auth headers, percent-encoding in URLs, Unicode in internationalization, and hex in cryptography. Getting them right matters, and getting them wrong causes hard-to-debug issues.
What Is the JWT Decoder?
JWT Decoder is one of the tools in WebdevToolbox’s Encoding & Decoding category. Decode and inspect JWT tokens — header, payload, and signature — without verification. It runs entirely in your browser — no server uploads, no accounts, no waiting.
How to Use It
- Open JWT Decoder.
- Paste your JWT token (starting with
ey...) into the input field. - The tool splits the token into header, payload, and signature — each decoded and pretty-printed.
- Check expiry, issuer, roles, or any custom claims without touching your backend.
Key Features
- 100% client-side — all processing happens in your browser. Nothing is sent to a server.
- Real-time output — results update as you type, with no submit button required.
- One-click copy — copy the output to your clipboard with a single button press.
- PWA-ready — works offline when installed as a Progressive Web App.
When to Use the JWT Decoder
- Auth headers — encode credentials for Basic Authentication or test Bearer token decoding.
- URL debugging — decode percent-encoded query strings to see the actual parameter values.
- Data embedding — convert binary assets to Base64 for embedding in HTML, CSS, or JSON.
Try It Now
Open JWT Decoder directly from anywhere on the site using ⌘K and typing the tool name. No login required — everything runs offline-capable in your browser.
Part of the Encoding & Decoding collection on WebdevToolbox — free, browser-based developer tools with no login required.