What is a JWT Decoder / Encoder?
A JWT Decoder / Encoder is an essential tool for developers working with authentication and authorization systems based on JSON Web Tokens (JWT). It allows you to decode a JWT to view its header, payload, and signature, or generate a new token by encoding structured data.
What is a JWT?
JWT (JSON Web Token) is a compact, URL-safe token format used to securely transmit information between parties. It consists of three parts: Header, Payload, and Signature. This tool lets you inspect or construct JWTs without sending any data to a server — everything runs locally in your browser.
Key Use Cases
- Decode JWTs to view and validate their contents.
- Encode data into a JWT for testing or learning purposes.
- Inspect tokens used in OAuth, OpenID Connect, Firebase, or API authentication systems.
- Debug signature issues by viewing raw base64 segments.
Features
- Decode JWTs into human-readable JSON
- Edit or paste custom headers and payloads
- Auto-format and syntax highlight JSON sections
- No data ever leaves your browser — secure and offline
- Supports both signed and unsigned tokens
Popular Keywords
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