JWT Decoder
Decode and inspect JSON Web Tokens (JWT) — view the header, payload claims, issue time, and expiration status instantly.
What Does This Tool Do?
A JWT (JSON Web Token) is a compact, encoded string used for authentication. It contains three base64-encoded sections: a header (algorithm info), a payload (claims like user ID and expiry), and a signature. This tool decodes the first two sections so you can read the contents — useful for debugging auth issues.
Key Features
How to Use This Tool
- Paste your JWT token into the Input box.
- Click Convert to decode and display the header, payload, and status.
- Check the INFO section for expiry status and timestamps.
How It Works
A JWT is three base64url-encoded sections separated by dots. This tool splits at the dots, adds back padding, and decodes each section with atob(). The decoded JSON is then displayed. Expiry is compared against the current time.
Common Use Cases
Frequently Asked Questions
Is it safe to decode JWTs here?
Decoding (reading) a JWT doesn't compromise security — it just reads what's inside. Never share JWTs with sensitive user data publicly, but decoding for inspection is fine.
Can it verify the signature?
No — signature verification requires the secret key, which only the server should have. This tool only decodes the header and payload.
Related Tools
Link to This Tool
Copy and paste the code below to link to this tool from your website: