JWT Token Input
Paste your JWT token to decode
Result will show here
What is JWT Decoder?
JWT Decoder is a tool for reading the contents of JWT (JSON Web Token) without verifying its digital signature.
JWT contains 3 parts:
- Header - Contains token type and signing algorithm
- Payload (claims) - Contains the actual data and claims
- Signature - Verifies the token hasn't been tampered with
The decoder helps developers quickly view payload contents for debugging purposes such as:
- Viewing roles / permissions
- Checking token expiration
- Verifying 'issuer' information
- Checking API 'scope'
- Validating token structure during auth implementation
🧪 JWT Decoder Use Cases
✔ 1. Debug Tokens from Authentication Providers
- Firebase Auth
- Auth0
- AWS Cognito
- Supabase
- Keycloak
✔ 2. Frontend Development
Check:
- Does the claim role=admin exist?
- Is token expired when users complain?
- Is the token structure correct?
✔ 3. Backend Development
Validate payload before writing verification in the backend.
✔ 4. QA / Testing
Check API tokens during API testing.
✔ 5. Security Review (Quick Inspection)
Check signature algorithm (alg) for security:
- HS256, RS256, ES256 → ✓ Secure
- NONE → ⚠️ Insecure
✔ 6. Debugging OAuth 2.0 / OpenID Connect
View:
iss- Issueraud- Audienceexp- Expirationnonce- Replay attack preventionazp- Authorized party
🧭 How to Use JWT Decoder
- Copy your JWT token
- Paste it in the input field
- The tool automatically separates header, payload, and signature
- View the decoded result: JSON + claim breakdown
- Use copy/export buttons if needed
⚠️ Important: This tool only decodes tokens, it does NOT verify signatures!