JWT Decoder & Validator
Free online JWT decoder. Decode JSON Web Tokens, view header and payload, check expiration dates. Understand JWT structure visually.
Decode and inspect JSON Web Tokens instantly. See the header, payload, and signature parts separately. Check if tokens are expired and understand the claims inside.
All decoding happens in your browser. Your tokens are never sent to any server, keeping your authentication data private.
How to Use This Tool
- 1 Paste your JWT token in the input field
- 2 The token is decoded automatically
- 3 Review the header to see the algorithm used
- 4 Check the payload for claims and user data
- 5 See if the token is expired or still valid
Use Cases
Debug Authentication
Inspect tokens during development to troubleshoot auth issues.
Check Expiration
Quickly verify if a token has expired and when.
Verify Claims
Confirm the payload contains expected user data and permissions.
Learn JWT Structure
Understand how JWTs are structured with visual breakdown.
Frequently Asked Questions
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe way to represent claims between parties. It's commonly used for authentication, containing a header, payload, and signature.
Is it safe to decode JWTs online?
JWTs are encoded, not encrypted. Anyone can decode them. The security comes from the signature verification, which requires the secret key. This tool never sees your secret.
What does the expiration claim mean?
The 'exp' claim is a Unix timestamp indicating when the token expires. After this time, the token should be rejected by servers even if the signature is valid.
Can this tool verify signatures?
No, signature verification requires the secret key used to sign the token. This tool only decodes and displays the token contents without verification.
What's the difference between HS256 and RS256?
HS256 uses a shared secret (symmetric), while RS256 uses public/private key pairs (asymmetric). RS256 is more secure for distributed systems.