JWT Parser
The JWT Parser is a free online tool that decodes and inspects JSON Web Tokens (JWT) directly in your browser. Paste any JWT to instantly see its decoded header, payload, and signature — color-coded for clarity following the standard jwt.io convention.
The tool automatically detects token expiration, converts Unix timestamps to human-readable dates, and provides syntax-highlighted JSON output. All parsing is done client-side — no data is ever sent to any server, making it safe for use with production tokens.
How it works
A JWT consists of three Base64URL-encoded parts separated by dots: Header (algorithm and token type), Payload (claims like sub, iat, exp), and Signature (cryptographic verification). The parser decodes the first two parts and displays the signature hash.
Use cases
- Debugging authentication issues by inspecting token claims and expiration
- Verifying JWT payload contents during API development and testing
- Checking if a token has expired or will expire soon
- Understanding token structure for OAuth 2.0 and OpenID Connect integrations
- Inspecting custom claims added by your identity provider