Does this tool verify JWT signatures?

No, this tool only decodes JWT tokens. It does not verify signatures, which requires the secret key or public key. For security, you should never share your secret keys with online tools. Use a server-side library for signature verification.

Is my JWT token sent to any server?

No, all decoding happens locally in your browser. Your JWT token is never transmitted to any server. This is especially important since JWT tokens often contain authentication data that should be kept private.

What are the standard JWT claims?

Standard claims include iss (issuer), sub (subject), aud (audience), exp (expiration time), nbf (not before), iat (issued at), and jti (JWT ID). These are defined in RFC 7519 and are commonly used in authentication tokens.

Why is my JWT decoding showing an error?

Common causes include: the input is not a valid JWT (must have three Base64url segments separated by dots), the token has been modified or corrupted, or the token includes non-standard encoding. Ensure you're pasting the complete token string.

Can I decode refresh tokens?

If the refresh token is a JWT (three dot-separated segments), it can be decoded. However, some providers use opaque tokens for refresh tokens, which are random strings without JWT structure and cannot be decoded this way.

What algorithm does my JWT use?

The signing algorithm is specified in the JWT header under the 'alg' field. Common algorithms include HS256 (HMAC with SHA-256), RS256 (RSA with SHA-256), and ES256 (ECDSA with SHA-256). The decoder shows this information prominently.

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JWT Token Decoder

A JWT decoder splits a JSON Web Token into its three Base64url-encoded parts (header, payload, signature) and decodes the header and payload into readable JSON. It reveals token claims, expiration, and algorithm but does not verify the signature.

100% FreeNo Signup RequiredBrowser-BasedPrivate & Secure

What is JWT Token Decoder?

A JWT decoder is a tool that decodes the Base64url-encoded header and payload sections of a JSON Web Token into readable JSON, revealing the token's claims, algorithm, and metadata without verifying the signature.

Complementary Tools

These tools work great alongside JWT Token Decoder:

Base64 Decode JSON Formatter & Validator

Start Using JWT Token Decoder Today

JWT tokens are opaque strings until you decode them. This tool splits the token into its three parts, decodes the header and payload, converts timestamps to readable dates, and highlights standard claims—all in your browser with zero server interaction. Decode your JWT now and see what's inside.

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