What is a JWT (JSON Web Token)?

JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed.

Is it safe to paste my JWT here?

Yes. Our JWT Decoder operates completely on the client-side within your browser. Your tokens are never sent to our servers, logged, or stored in any way, ensuring complete privacy.

Can this tool verify the signature of my JWT?

This specific tool is designed for quickly decoding and inspecting the contents of the Header and Payload. It decodes the Base64Url encoded segments to make them human-readable, but it does not currently validate the cryptographic signature.

Why does a JWT have three parts?

A standard JWT consists of three parts separated by dots (.). They are: Header (algorithm & token type), Payload (the actual data or claims), and Signature (used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn't changed along the way).

Can I edit the JWT and re-encode it?

Currently, this tool is purely a decoder for inspection. If you edit the payload, you would need to re-sign the token with the appropriate secret key to create a valid JWT, which usually happens on the backend.

What is a JWT (JSON Web Token)?

JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed.

Is it safe to paste my JWT here?

Yes. Our JWT Decoder operates completely on the client-side within your browser. Your tokens are never sent to our servers, logged, or stored in any way, ensuring complete privacy.

Can this tool verify the signature of my JWT?

This specific tool is designed for quickly decoding and inspecting the contents of the Header and Payload. It decodes the Base64Url encoded segments to make them human-readable, but it does not currently validate the cryptographic signature.

Why does a JWT have three parts?

A standard JWT consists of three parts separated by dots (.). They are: Header (algorithm & token type), Payload (the actual data or claims), and Signature (used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn't changed along the way).

Can I edit the JWT and re-encode it?

Currently, this tool is purely a decoder for inspection. If you edit the payload, you would need to re-sign the token with the appropriate secret key to create a valid JWT, which usually happens on the backend.

JWT Decoder

Decode JSON Web Tokens (JWT) easily and securely view the header, payload, and signature.

Encoded JWT

Header (Algorithm & Token Type)

{}

Payload (Data)

{}

Signature (Verify)

...

How it works

Three simple steps to decode your JSON Web Tokens.

Input JWT

Paste your encoded JWT string into the input field.

Instant Decoding

The tool automatically decodes the Base64Url encoded segments.

View Data

Inspect the clearly formatted Header and Payload JSON structures.

eyJhbGciOi....eyJzdWIiOi....SflKxwRJSMe...

HEADER: ALGORITHM & TOKEN TYPE

{
  "alg": "HS256",
  "typ": "JWT"
}

PAYLOAD: DATA

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022
}

Built for secure decoding

A fast and reliable tool to inspect JSON Web Tokens locally.

100% Client-Side Decoding

Your JWTs never leave your device. All decoding happens directly within your browser ensuring your tokens remain private and secure.

Instant Inspection

Immediately view the decoded Header and Payload of your JSON Web Token in an easy-to-read formatted structure.

Clear Structure Breakdown

Automatically separates the JWT into its three parts (Header, Payload, Signature) and highlights them for quick analysis.

Understand Your JWTs with our Free Decoder

JSON Web Tokens (JWT) are a crucial part of modern web development, particularly for authentication and secure information exchange. However, because they are encoded as Base64Url strings, you can't simply read them at a glance. Our JWT Decoder is designed to solve this problem instantly. Whether you are debugging an API, verifying claims, or just learning how JWTs work, this tool provides a clear, formatted view of your token's internal structure without compromising security.

Anatomy of a JSON Web Token

If you look at a JWT, you will notice it is composed of three strings separated by dots (.). Each part serves a distinct purpose:

Header: Typically consists of two parts: the type of the token (which is JWT) and the signing algorithm being used, such as HMAC SHA256 or RSA.
Payload: Contains the claims. Claims are statements about an entity (typically, the user) and additional data. These can be registered, public, or private claims.
Signature: To create the signature part you have to take the encoded header, the encoded payload, a secret, the algorithm specified in the header, and sign that.

Why Privacy Matters

JWTs often contain sensitive information about your users or your system architecture. Pasting production tokens into random online tools can be a massive security risk if those tools log or transmit the data. Our JWT Decoder is built with a privacy-first approach. The decoding logic is executed entirely in your browser using JavaScript. Your token never travels over the network, ensuring that your data remains strictly on your machine.

Common Use Cases

Debugging Authentication: Quickly verify if the token issued by your backend contains the correct user ID, roles, and expiration times.
API Integration: When consuming third-party APIs, decode their tokens to understand the payload structure they expect or return.
Learning & Education: Visually break down the components of a JWT to better grasp the standard RFC 7519 specification.

While JWTs are excellent for stateless authentication, managing them requires good tooling. Once you have decoded your token and understand its contents, you might need to work with other data formats. Explore our JSON to YAML Converter or other utilities in the Security Tools category to streamline your development workflow.

JWT Decoder

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