JSON Studio

JWT Decoder & Inspector

Decode and inspect JSON Web Tokens instantly. Visually separate the Header, Payload, and Signature to debug authentication issues directly in your browser.

Encoded JWT
Decoded Token

Waiting for valid JWT

Paste a JSON Web Token to decode its Header and Payload.

🛡️

Local-first JWT inspection: data stays local

Decoding and inspecting JSON Web Tokens occurs strictly on your device. Your credentials, claims, and signature headers never touch a remote server.

Secure, Client-Side Decoding

JSON Web Tokens are the industry standard for securing APIs and authenticating users. Because these tokens often contain sensitive claims, this tool performs all decoding strictly on your device using browser-native Base64Url algorithms. Your tokens are never sent to a server.

Understanding JWT Structure

🔴 Header

Contains metadata about the type of token and the cryptographic algorithm used to secure it (e.g., HS256, RS256).

🟣 Payload

Contains the claims or statements about an entity (typically, the user) and additional data like expiration times (exp) or issued-at times (iat).

🔵 Signature

Used to verify that the token was not changed along the way. This tool securely unpacks the visible data to assist in rapid debugging.

Related JSON Tools

Format the decoded payload for easier reading. Use the JSON Viewer to explore complex JWT claims. Compare two tokens side by side.

Frequently Asked Questions

A JWT (JSON Web Token) is a compact, URL-safe token format used for authentication and authorization. This tool decodes the header, payload, and signature sections so you can inspect claims like expiration time, issuer, and custom data.
The tool decodes and displays JWT contents. Signature verification requires the secret key or public key, which should never be pasted into any online tool. Use this for inspection only.
Yes. The JWT decoding runs 100% in your browser. No token data, claims, or header information is ever sent to a server. We help you inspect tokens securely without exposing them to the internet.
The decoder works with any JWT regardless of algorithm (HS256, RS256, ES256, etc.) because it decodes the base64url-encoded payload without verifying the signature.

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