JWT Decoder
Decode and inspect JWT token payload and header.
About JWT Decoder
JWT Decoder Base64-decodes a JSON Web Token and displays its header and payload sections as formatted JSON without requiring a secret key. This lets you quickly inspect claims like user ID, roles, issuer, and expiry when debugging authentication flows. Note that decoding does not verify the signature — use this tool for inspection only, not to trust the token contents.
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Frequently Asked Questions
Is JWT Decoder free?
Yes, completely free. No signup, no account, no usage limits. Use it as much as you need.
Is my data secure?
All processing happens directly in your browser using JavaScript. Your data is never sent to any server, stored, or shared. It stays entirely on your device.
Does decoding a JWT verify that the signature is valid?
No. Decoding only reads the Base64-encoded payload. Signature verification requires the secret or public key and should be done by your server or auth library.
Is it safe to paste a real JWT into this tool?
Be cautious with production tokens. All processing happens in your browser and nothing is sent to a server, but as a best practice avoid pasting live tokens with sensitive claims into any online tool.