How to Inspect and Decode JWT Tokens Safely in Your Browser
Never paste production JWT tokens with sensitive session claims into public debugging websites. Discover how JWT encoding works and how to safely inspect claims client-side.
A JSON Web Token consists of three base64url-encoded parts separated by dots: Header, Payload, and Signature. You can inspect claims safely using our client-side JWT Token Inspector, which parses claims purely with JavaScript and never transmits tokens over the network.
JWT Token Inspector
Decode and inspect JSON Web Tokens with header, payload and claims
Table of Contents
The 3 Parts of a JSON Web Token
A standard JWT looks like a long continuous string: `eyJhbGciOiJIUzI1Ni... . eyJzdWIiOiIxMjM... . SflKxwRJSMeKKF2...`
It is simply 3 Base64URL-encoded JSON objects concatenated with periods (`.`):
1. Header (Red): Declares the token type (`JWT`) and hashing algorithm (`HS256`, `RS256`). 2. Payload / Claims (Purple): The data payload, such as user identity, permissions, and expiration timestamp. 3. Signature (Blue): A cryptographic HMAC or RSA signature ensuring the token was not tampered with.
Security Risks of Online Decoders
Many popular JWT debuggers send tokens to their backend servers for logging, analytics, or caching. If you paste a production Bearer token containing: - User email and internal employee IDs - OAuth authorization scopes - Session IDs or tenant metadata
You may violate privacy regulations (GDPR/HIPAA) or risk session hijacking if the token is still valid.
How to Safely Decode JWTs with OmniToolBox
Our JWT Token Inspector operates 100% in-browser: 1. Paste your token into the inspector. 2. The browser automatically extracts the JSON objects using client-side Base64URL decoding. 3. Check the expiration date (`exp`) to see if the session is still active. 4. Verify standard claims (`sub`, `iss`, `aud`) without a single byte crossing the network.
Frequently Asked Questions
Is a JWT encrypted or just encoded?▼
Standard JWTs (JWS) are encoded with Base64URL, NOT encrypted. Anyone who intercepts the token can read the payload. They only prevent tampering via the signature. For sensitive payload encryption, JWE (JSON Web Encryption) is used.
Related Free Tools
Global User Reviews & Feedback
0Real reviews from users across 50+ countries. Published instantly client-side!