Base64 Encoder & Decoder
Encode UTF-8 text to Base64 or decode Base64 locally in your browser.
Developer
Free JWT Decoder
Decode JSON Web Token header and payload locally without uploading the token or pretending to verify its signature.
Your input is processed only as required by this tool.
Free JWT Decoder
A JWT normally contains three dot-separated segments: header, payload and signature. The first two segments are Base64URL-encoded JSON. This decoder reads those JSON objects in your browser so you can inspect claims such as issuer, subject, audience and expiration during development or troubleshooting.
How to use it
- Paste or type the value you want to process.
- Choose the operation or algorithm when the tool offers options.
- Generate the result locally in your browser, then copy it without uploading the input to Ciatto Tools.
How to read the result
Decoded claims are not proof that a token is authentic. Signature verification requires the correct key, accepted algorithms and application-specific validation rules. This tool deliberately labels the output as decoded only.
Limitations
Do not rely on decoded content for authorization or security decisions. A malicious party can construct an unsigned or incorrectly signed token containing arbitrary claims. Verification belongs in your trusted application or identity system.
Frequently asked questions
Does this JWT decoder verify signatures?
No. It only decodes the header and payload and explicitly reports that the signature has not been verified.
Is my JWT uploaded?
No. The token is decoded locally in your browser.