What is JWT Decoder?
JWT Decoder is a free browser-based tool that parses JSON Web Tokens (JWTs) and displays their contents in a readable format. When you paste a JWT token, the decoder extracts the header and payload, shows expiration timestamps, and highlights whether the token has expired. This jwt decoder online runs entirely in your browser — no data is sent to external servers, keeping your tokens private and secure.
Unlike verification tools, JWT Decoder focuses solely on inspecting token contents. It does not validate signatures or check token authenticity. If you need to examine what’s inside a JWT without verifying it against a secret, this tool handles that instantly.
How to Use JWT Decoder
- Paste your JWT token into the input field
- The tool automatically parses the header and payload
- Review the decoded JSON output for both sections
- Check the expiration date (if present) — expired tokens are highlighted in red
- Copy the decoded JSON to your clipboard if needed
The decoder handles standard JWT tokens with three Base64url-encoded sections separated by dots. Malformed tokens display an error message with details about what went wrong.
When to Use This Tool
- Debugging authentication issues by inspecting token claims
- Verifying token expiration dates before making API calls
- Examining token structure during development
- Checking user roles, permissions, or custom claims in the payload
- Learning how JWTs are structured and what data they contain
FAQ
Does JWT Decoder verify token signatures?
No. This tool only decodes and displays token contents. It does not validate signatures or authenticate tokens against a secret key.
Is my JWT token sent to a server?
Never. This jwt decoder online runs entirely in your browser using client-side JavaScript. Your tokens remain private and are never transmitted over the network.
Try the JWT Decoder now to inspect your tokens instantly with zero setup. For a deeper dive, see our What is JWT guide.