JWT Standard Claims Decoder & Reference

Decode and understand JWT standard claims: sub (subject), iss (issuer), aud (audience), iat (issued-at), nbf (not-before), and jti (JWT ID).

AUTH DEBUG

JWT Decoder

> Decode JWT header and payload locally in your browser.
> Inspect exp, iat, and nbf claims without sending bearer tokens to third-party sites.

JWT or Bearer token

Decode only

This tool decodes header and payload locally. It does not verify the signature or prove the token is trustworthy.

Header JSON

// Decoded JSON appears here...

Payload JSON

// Decoded JSON appears here...

Claim timing

Header, payload, signature segment state, and timestamp analysis will appear here.

Signature segment

// Signature segment appears here...

What this tool can and cannot tell you

Can decode header/payload structure locally.
Can show readable timestamps for exp, iat, and nbf.
Cannot verify the cryptographic signature.
Cannot prove the token was issued by the expected system.

Complete Guide to JWT Standard Registered Claims

The JWT specification (RFC 7519) defines seven registered claims that carry standardized meaning across all compliant JWT implementations. sub (subject) typically carries the user ID. iss (issuer) identifies the authority that generated the token (e.g., accounts.google.com). aud (audience) specifies which services should accept the token. iat (issued-at) and exp (expiration) define the token's lifetime. nbf (not before) prevents the token from being used too early. jti (JWT ID) is a unique identifier used to prevent replay attacks. Our decoder clearly labels each of these registered claims and separates them from private (custom) claims added by your application.

FAQ

What is the sub claim in a JWT?

The sub (subject) claim identifies the principal that is the subject of the JWT — typically the user ID or account ID in your application. It is a string and must be unique within the context of the issuer.

You May Also Need

Base64

Encode and decode text to/from Base64 format with UTF-8 support.

URL Encoder

Encode and decode URL components or form values with UTF-8-safe browser processing.

JSON Formatter

Validation, formatting and syntax highlighting for JSON.

Password Generator

Cryptographically secure password generator.

View all tools in this category →

Claim timing

Header, payload, signature segment state, and timestamp analysis will appear here.

Signature segment

// Signature segment appears here...

What this tool can and cannot tell you

Can decode header/payload structure locally.
Can show readable timestamps for exp, iat, and nbf.
Cannot verify the cryptographic signature.
Cannot prove the token was issued by the expected system.

Complete Guide to JWT Standard Registered Claims