DEV 📝 Text Utilities

JWT Encoder & Decoder

JSON Web Tokens (JWT) are a compact way to transmit data between parties as a JSON object. This tool decodes JWTs to inspect their header and payload, or encodes a JSON payload into a JWT with base64url encoding. Note: actual signature computation should be done server-side with your secret key.

How to Use

  1. For Decode mode: paste a JWT token (3 dot-separated base64url parts) into the input.
  2. For Encode mode: enter a JSON payload and choose a header template.
  3. Click Transform to process the token.
  4. Click Copy to copy the result.

How It Works

JWT structure: header.payload.signature. Each part is base64url-encoded JSON. The decoder reverses base64url encoding and parses the JSON. The encoder applies base64url encoding to the header and payload. The signature placeholder reminds you to sign server-side.
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