JWT Decoder
Decode JSON Web Tokens (JWT) and inspect header, payload, and signature. Pretty-printed JSON output. All processing is local.
Decode Token
No token yet
Paste a JWT above and click Decode Token to inspect its contents
What this tool does not do
- Does not validate or verify the JWT signature.
- Does not support encrypted JWTs (JWE).
- For signature generation and testing, use the JWT Generator tool.
How It Works
Paste token
Copy and paste any JWT into the input field. The tool accepts standard three-part tokens separated by dots.
Decode
Each part is base64url-decoded. The header and payload are parsed as JSON and displayed with syntax highlighting.
Inspect
Review the algorithm, token type, claims, and signature. All processing stays in your browser.
Frequently Asked Questions
What is a JWT?
JWT (JSON Web Token) is an open standard for securely transmitting information as a JSON object. It consists of three parts: header, payload, and signature, separated by dots.
Is my JWT uploaded to a server?
No. All JWT decoding happens entirely in your browser. Your token never leaves your device.
Does this tool validate the signature?
This tool decodes and displays the three parts of a JWT. Signature validation is not performed — use the JWT Generator tool for development and testing with signature support.