JWT Decoder & Token Parser
Decode JSON Web Tokens (JWT) locally. View token metadata, claims, issue dates, and validation status instantly.
How to Use JWT Decoder
- Paste your encoded JSON Web Token (JWT) string into the inputs text box.
- The decoder automatically splits the token into its three constituents: Header, Payload, and Signature.
- Review the parsed JSON elements. The Header details the signing algorithm; the Payload lists the token claims and metadata.
- Examine the 'Token Expiry Status' panel, which automatically parses 'exp' and 'iat' claims and shows token expiration dates.
- Copy header or payload elements using the corresponding 'Copy' buttons.
Key Features & Privacy Guarantee
- Instant Automated Decoding: Extracts and parses JWT parts on-the-fly as you paste or type.
- Claim Expiry Diagnostics: Converts unix epochs ('exp', 'iat', 'nbf') to readable local dates and highlights current validation status.
- Zero Client-Server Latency: Operates entirely inside client-side JS context, keeping private Auth tokens out of remote logs.
- Structured JSON Outputs: Prettifies headers and payload bodies with clean color schemes and fonts.
Frequently Asked Questions
What is a JWT (JSON Web Token)?
A JWT is a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is digitally signed using cryptography (HMAC, RSA, or ECDSA) to verify that the sender is authentic and the contents haven't been altered.
What are the three parts of a JWT?
A JWT consists of three parts separated by dots (header.payload.signature). 1. Header: contains token type and signing algorithm (e.g. HS256). 2. Payload: contains claims (statements about user, metadata, permissions). 3. Signature: generated by hashing the header and payload with a secret key.
Does this tool verify the signature of the JWT?
No. This tool is a decoder, not a signature verifier. It decodes the Base64Url segments of the token to show you what claims are inside. To verify the signature, you must possess the secret key or public certificate and run verification algorithms locally on your server.
Is pasting my JWT token here secure?
Yes. Our JWT Decoder performs all computations entirely in your browser using JavaScript. No tokens or keys are sent to the network. However, be cautious when using online utilities for production JWTs; always ensure the page loads over secure HTTPS.