JWT Decoder & Debugger
Developer utilities: formatters, validators, encoders, and testers.
What does this tool do?
Debug JSON Web Tokens without risking your secrets. Paste any JWT to decode its header and payload client-side, inspect claims like expiry, and verify token structure - your token never leaves this page.
Key features
- Syntax validation
- Format & minify
- Error highlighting
- Copy formatted output
Debug JSON Web Tokens without risking your secrets. Paste any JWT to decode its header and payload client-side, inspect claims like expiry, and verify token structure - your token never leaves this page.
JWT Input
Privacy: decoding happens 100% in your browser. This page makes zero network requests with your token.
Header
Payload
Signature
The signature cannot be verified without the secret key - this tool only decodes, it never validates trust.
Claim Analysis
How to Use
- Paste your JWT (three Base64URL parts separated by dots) into the input box.
- The header, payload and signature decode instantly with claim analysis below.
- Use Load sample token to see how a decoded token looks.
Core Features
- Zero network requests - your token never leaves this browser tab
- Pretty-printed header and payload with syntax-friendly formatting
- Automatic expiry check: shows if the token is expired and time remaining
- Sample token generator for learning and testing
Frequently Asked Questions
Is it safe to paste a real production token here?
Yes. All decoding runs locally with JavaScript - open your browser devtools Network tab and you will see zero requests. Still, avoid pasting tokens on shared computers as a general habit.
Why does it say the signature cannot be verified?
Signature verification needs the secret or public key, which this tool intentionally never asks for. Decoding shows you what is inside the token; always verify signatures on your own server.
How to Use JWT Decoder & Debugger
Reviews & Comments
No reviews yet. Be the first to share your experience!
Your feedback helps others discover great tools.