JWT Decoder

Decode JSON Web Tokens instantly in your browser

View header, payload, claims, and check expiration status

JWT format: header.payload.signature

What is JWT Decoding?

JWT decoding is the process of parsing a JSON Web Token to extract and read its contents. A JWT consists of three Base64URL-encoded parts separated by dots: the header (which contains metadata about the token type and signing algorithm), the payload (which contains the claims or actual data), and the signature (which is used to verify the token hasn't been tampered with). Unlike encryption, JWT encoding is not meant to hide data - anyone with the token can decode and read it.

How to Use the JWT Decoder

1

Paste your JWT token

Copy your JWT token and paste it into the input textarea. You can also click the 'Paste' button to automatically paste from your clipboard.

2

Automatic decoding

The tool automatically decodes your token as you type or paste. There's no need to click any decode button - results appear instantly.

3

Review the decoded sections

The header shows the token type and algorithm. The payload displays all claims including standard ones like 'iat' (issued at), 'exp' (expiration), and custom claims.

4

Check expiration status

The tool automatically checks the 'exp' claim and shows whether your token is valid, expired, or has no expiration set.

Why Use Our JWT Decoder?

Complete privacy

All JWT decoding happens locally in your browser using native JavaScript. Your tokens never leave your device, ensuring maximum security for sensitive authentication data.

Instant results

No waiting, no page reloads. Your JWT is decoded in real-time as you type or paste, making debugging authentication issues faster and easier.

Expiration monitoring

Automatically check if your token has expired or is still valid. The tool displays the exact expiration time in a human-readable format.

Color-coded sections

Easily distinguish between header, payload, and signature with color-coded sections. Each part is clearly labeled and formatted for readability.

Copy functionality

Easily copy individual sections (header, payload, or signature) to your clipboard with one click. Perfect for debugging and documentation.

Frequently Asked Questions

A JSON Web Token (JWT) is a compact, URL-safe means of representing claims between two parties. It consists of three parts: a header (specifying the token type and signing algorithm), a payload (containing the claims or data), and a signature (used to verify the token's integrity). JWTs are commonly used for authentication and information exchange in web applications.
Yes, absolutely! All JWT decoding happens locally in your browser using JavaScript. Your token data is never sent to any server. However, be cautious about sharing sensitive tokens, as the data in a JWT payload is not encrypted - it's just base64 encoded and can be read by anyone who has the token.
JWT tokens have an 'exp' (expiration) claim that specifies when the token should no longer be accepted. If your token shows as expired, it means the current time is past the expiration timestamp. You'll need to obtain a new token from your authentication server. The expiration time is typically set by the server that issued the token.
No, this tool only decodes JWT tokens to show their contents. It cannot verify the token's authenticity because verification requires the secret key or public key used to sign the token. Verification should be done server-side where the signing key is available. This tool is useful for debugging and inspecting token contents during development.

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