JWT Decoder

JWT Token
Header
Decoded Header JSON will appear here
Payload
Decoded Payload JSON will appear here
Signature Info
Signature—
Encoded0 chars

JWT Decoder - Online JSON Web Token Parser

JWT Decoder is a client-side online tool for decoding JSON Web Tokens (JWT). You can quickly inspect the Header and Payload without sending your token to any server, ensuring your credentials remain secure.

Key Features

  • Auto Decode: Paste a JWT token and instantly see the decoded Header and Payload
  • Clear Layout: Header (algorithm & type), Payload (claims & data), and Signature info displayed separately
  • One-click Copy: Copy Header or Payload JSON content individually
  • Privacy First: All decoding happens locally in your browser — your token never leaves your device

What is JWT?

JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way to securely transmit information between parties as a JSON object. It consists of three parts: Header, Payload, and Signature.
  • Header: Contains the token type (typ) and signing algorithm (alg), such as HS256 or RS256
  • Payload: Contains the claims — the actual data being transmitted, such as user ID, roles, or expiration time

Use Cases

  • Authentication Debugging: Verify and analyze JWT tokens returned by APIs
  • Security Audit: Inspect claims and permissions embedded in tokens
  • Development Testing: Quickly view Header and Payload during development
  • Learning: Visualize JWT structure to better understand how it works

Privacy Notice

This tool never sends your JWT token to any server. All parsing happens entirely in your browser. Your token never leaves your device.