Developer Tools5 min read•2026-05-30
JWT Decoder Free: Decode JSON Web Tokens Online
By FreeToolbox Team
JWT Decoder Free: Decode JSON Web Tokens Online
Need to decode a JWT token? Our free decoder shows header, payload, and expiration status.
What is a JWT?
JWT (JSON Web Token) securely transmits information between parties. Common for authentication in web apps.
Structure: Header.Payload.Signature
JWT Structure
| Part | Purpose | Encoded As |
|---|---|---|
| Header | Algorithm, token type | Base64URL |
| Payload | Claims (user data, expiry) | Base64URL |
| Signature | Verification | Hash |
What You Can See
Header - Algorithm (HS256, RS256) - Token type (JWT)
Payload Claims - sub: Subject (user ID) - iat: Issued at - exp: Expiration time - name, email, role
Signature - Cannot be decoded (it is a hash)
FreeToolbox JWT Decoder
Features: - 100% free, no registration - Decode header and payload - Pretty-printed JSON - Check if expired - Browser-based (private)
Try: [JWT Decoder](/tools/jwt-decoder)
How to Use
- Paste JWT token
- Click Decode
- View header, payload, expiration
Common Use Cases
- Debug authentication flows
- Check token expiry
- API testing
- Security auditing
Security Notes
JWTs are encoded, NOT encrypted. Anyone can decode the payload.
- OK to include: name, email, role
- NEVER include: passwords, SSN, API keys
- Always include: exp (expiration)
Frequently Asked Questions
**Q: Can JWTs be encrypted?** A: JWE (JSON Web Encryption) encrypts. Standard JWTs are only signed.
**Q: Can someone forge a JWT?** A: Only with the signing secret. Signature prevents tampering.
[JWT Decoder](/tools/jwt-decoder)