Free JWT Decoder Online | Decode & Inspect JSON Web Tokens | SkyBrance

What is a JWT Token?

JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. JWTs are commonly used for authentication and authorization in web applications, APIs, and microservices. A JWT consists of three parts: a header (algorithm and type), a payload (claims/data), and a signature (verification).

Our JWT decoder lets you inspect the contents of any JWT without needing a secret key. This is useful for debugging authentication flows, verifying token claims, checking expiration times, and understanding what data is being transmitted. Your token is saved in localStorage so it persists across page reloads.

Key Features

Instant Decoding

Decode JWT header, payload, and signature with a single click.

100% Client-Side

Your tokens never leave your browser. No data sent to any server.

Expiry Detection

Automatically detects and displays token expiration status (valid/expired).

Persistent Storage

Token is saved in localStorage - reload the page and it's still there.

Frequently Asked Questions

Is it safe to paste my JWT here?

Yes. All decoding happens entirely in your browser using JavaScript. No data is transmitted to any server. The token is stored in your browser's localStorage for convenience. Clear it anytime with the Clear button.

Can this tool verify JWT signatures?

No. This tool only decodes (reads) the token contents. Signature verification requires the secret key or public key, which should never be exposed in a browser tool. The secret field is for your reference only.

What claims does the tool detect?

The tool automatically detects and displays exp (expiration time) and iat (issued at) claims with human-readable timestamps and validity status.

What JWT algorithms are supported?

Since we only decode (not verify), all algorithms are supported: HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, ES512, PS256, etc.

About the JWT Decoder

A JSON Web Token (JWT) packs a header, a payload of claims, and a signature into a single compact string. The JWT Decoder splits that string apart and shows you the decoded header and payload in readable JSON, along with useful details like the issued-at and expiry times. It is the fastest way to check what is inside a token while debugging authentication.

Frequently asked questions

Does this tool verify the JWT signature?

Decoding shows the contents of a token but does not by itself prove the token is authentic. Signature verification requires the secret or public key and should be done server-side. This tool focuses on inspecting the decoded claims.

Is it safe to paste a real token here?

Decoding happens entirely in your browser and nothing is sent anywhere. That said, treat production tokens as secrets and avoid sharing them.

Why is the payload readable without a key?

A JWT payload is Base64Url-encoded, not encrypted. Anyone can decode and read it, which is why you should never put sensitive secrets in a JWT payload.

How do I know if a JWT is expired?

Look at the exp claim, which is a Unix timestamp. If that time is in the past, the token has expired. This tool highlights the expiry status for you.

Free Online JWT Decoder