JWT Decoder — Free Online Tool
Decode the header and payload of a JSON Web Token without verifying the signature.
About JWT Decoder
The JWT Decoder splits a JSON Web Token on its dots and Base64URL-decodes the header and payload, then pretty-prints each as readable JSON. It is the fast way to inspect the claims inside a token while debugging authentication flows and API integrations.
All decoding is performed locally in your browser with no signature verification and no network calls, so your token stays private. Because it does not validate signatures, use it only for inspection and always verify tokens server-side before trusting them.
How to Use JWT Decoder
- Paste your JWT in the xxxxx.yyyyy.zzzzz format into the input box.
- Click 'Decode' to split and decode the token.
- Read the formatted header and payload JSON in their boxes.
- Use the copy buttons to grab the header or payload.
Key Features
Decodes and pretty-prints the JWT header and payload
Handles Base64URL encoding and Unicode characters correctly
Separate copy buttons for the header and payload
No signature verification means no keys are ever needed
100% client-side processing for complete privacy
Frequently Asked Questions
What parts of a JWT does this tool decode?
It decodes the first two segments of a token: the header, which describes the algorithm and type, and the payload, which holds the claims. Both are Base64URL-decoded and pretty-printed as JSON.
Does it verify the token's signature?
No. This tool only decodes and displays the contents; it does not check the signature. Never trust a decoded token for authentication without verifying its signature on a trusted server.
Is it safe to paste a real token here?
Decoding happens entirely in your browser and nothing is uploaded, so the token never leaves your device. Still, treat any live token as a secret and avoid sharing your screen while it is visible.
Why does my payload show numbers for dates?
JWT timestamps such as exp and iat are stored as Unix epoch seconds. Use a timestamp converter to turn those numbers into readable dates.