JWT Decoder
Decode and inspect JSON Web Tokens instantly, viewing the header, payload and expiry, right in your browser. No signup, no backend, no data ever leaves your device.
✅ Reviewed by Rashid Amin, Founder of NexaTools 🕒 Last Updated: July 2026
JWT Input
🔑 Client-Side OnlyFree Online JWT Decoder
What Is a JWT Decoder?
A JSON Web Token is a compact, three-part string used to carry identity and session data between a client and a server. A JWT decoder splits that string at its two dots and base64url-decodes each section, turning the header and payload back into readable JSON so you can see exactly what claims a token carries, such as a user ID, roles, or an expiry time.
The NexaTools JWT Decoder does this entirely in your browser. Nothing you paste is sent to a server, which matters because tokens often carry live session data you don't want leaving your machine.
How to Decode a JWT
Paste your token
Drop the full JWT string, header.payload.signature, into the input box above.
Click Decode
The tool splits and base64-decodes each section instantly.
Inspect the claims
Review the header, payload and expiry, or copy the payload JSON.
Why Use This JWT Tool
Private by design. Tokens never leave your browser or touch a server.
Instant results. Decoding happens the moment you click, no waiting on a backend.
100% free. No signup, no usage limits, no watermark on the output.
Works everywhere. Fully responsive on desktop, tablet and mobile browsers.
Who Should Use This Tool
This JWT decoder is built for anyone working with token-based authentication who needs to see what's actually inside a token. That includes:
Developers debugging authentication flows who need to see the claims an API issued.
Backend and API engineers confirming a token's payload contains the expected fields during integration testing.
Students and hobbyists learning how JWTs are structured and how header, payload and signature fit together.
Anyone without dev tools installed who needs to quickly check a token's contents without writing a script.
Common Use Cases
Debugging login and session issues. Decode a token to confirm which claims and roles it actually contains.
Checking token expiry. See the "exp" claim converted to a readable date to confirm whether a token has expired.
Verifying API responses. Confirm a token issued during testing contains the fields your application expects.
Learning JWT structure. Explore how the header, payload and signature sections are separated and encoded.
Common Problems & Troubleshooting
"Invalid Token" error. Make sure you copied the full token with all three dot-separated sections (header.payload.signature) and no extra whitespace.
Copy button doesn't seem to work. Some browsers block clipboard access until you interact with the page first; click anywhere on the page, then try Copy Payload again.
I need to verify the signature, not just decode it. This tool only decodes and displays the header and payload; verifying a signature requires the signing key and isn't something this browser-only tool performs.
Be careful where you paste real tokens. JWTs often carry live session data, so avoid pasting production tokens into any tool unless you trust it runs entirely client-side, as this one does.
Frequently Asked Questions
Inspect Your JWT in Seconds
Paste, decode, review no login required, ever.