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JWT Decoder

Online tool to decode JSON Web Token (JWT) Header and Payload content. All operations are performed locally, secure and reliable.

JWT Token

Features​

  • 🔒 Local Processing: All operations are done in browser, token is never uploaded
  • ⚡ Real-time Decoding: View results instantly as you type
  • 🎨 Formatted Display: Automatically format JSON data for better readability
  • 📋 Error Prompts: Clear error messages for invalid formats

About JWT​

JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. A JWT consists of three parts:

  1. Header: Contains token type and signing algorithm
  2. Payload: Contains the claims
  3. Signature: Used to verify the message hasn't been changed along the way

FAQ

What can I see after decoding a JWT?
You can see the Header (token type and signing algorithm) and the Payload (claims such as user ID, role, expiry time). Note that decoding is not the same as verifying the signature — anyone can decode a JWT.
How do I check when a token expires?
The exp field in the Payload is the expiration time, a Unix timestamp (seconds since 1970-01-01). iat is the issued-at time and nbf is the not-before time. Decode the token with this tool and read these fields.
What is the relationship between JWT and OAuth?
JWT is a token format standard, while OAuth 2.0 is an authorization framework. In OAuth 2.0, JWT is often used as the format for access tokens or ID tokens, but they are different concepts — JWT can also be used outside OAuth.
Is decoding a JWT safe?
A JWT's Header and Payload are only Base64Url-encoded, not encrypted, so anyone can decode them. This tool decodes entirely in your browser and never sends the token to any server. However, never expose your JWT in public.
What are the common claims in a JWT?
Common fields include: iss (issuer), sub (subject), aud (audience), exp (expiration), iat (issued at), nbf (not before), jti (JWT ID). Besides these standard fields, custom business fields can also be included.
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