JWT Decoder & Debugger

Paste a JSON Web Token to instantly decode the header and payload, interpret standard claims, and verify HMAC or RSA signatures. Decodes live as you type.

Encoded Token

Paste a JWT on the left to see the decoded header, payload, and claims here.

Header · Payload · Signature

Header

Payload

Claims Breakdown

Claim	Name	Value

About the JWT Decoder

JSON Web Tokens (JWTs) are a compact, URL-safe way to represent claims between two parties. This free JWT debugger decodes any JWT instantly — displaying the header algorithm, payload claims, and providing human-readable interpretations of standard claims like expiry times, issuer, and subject.

Features

Live decoding — token is decoded instantly as you type
Colour-coded token display — header (red), payload (purple), signature (cyan)
Syntax-highlighted JSON for header and payload
Claims breakdown table with human-readable names for all standard claims
Expiry status — shows whether the token has expired and by how much
Signature verification — supports HMAC-SHA256/384/512 and RSA/PS algorithms
Base64URL-encoded secret support
100% client-side — your tokens never leave your browser

What is a JWT?

A JWT consists of three Base64URL-encoded parts separated by dots: a header (algorithm and token type), a payload (claims), and a signature (used to verify the token hasn't been tampered with). JWTs are widely used for authentication and authorisation in REST APIs and web applications.

Standard claims

iss — Issuer: who issued the token
sub — Subject: who the token is about
aud — Audience: who the token is intended for
exp — Expiry: Unix timestamp after which the token is invalid
nbf — Not Before: Unix timestamp before which the token is invalid
iat — Issued At: Unix timestamp when the token was issued
jti — JWT ID: unique identifier for the token

Security note

This tool runs entirely in your browser. Your JWT and signing secrets are never transmitted to any server. However, you should still avoid pasting production tokens with sensitive claims into any online tool where possible.