What this tool does
Decodes JSON Web Tokens (JWT) and explains header, payload, and signature structure.
This page focuses on practical, step‑by‑step usage for **JWT Token Debugger**, with clear examples and common pitfalls.
When you should use it
Use it to troubleshoot auth issues, check claims, and verify whether a token is expired or malformed.
How to use
- Paste the JWT.
- The tool decodes header/payload and flags common pitfalls.
- Optionally verify signature if you provide the right key.
Quick example
Example: Confirm the ‘exp’ claim time and the signing algorithm (HS256/RS256).
Notes
Never paste live production tokens into a public machine; use redacted or test tokens.
JWT Token Debugger
Comprehensive JWT token analysis with decoding, validation, and security auditing
Complete JWT Token Analysis:
Decode JWT tokens into header, payload, and signature components
Validate token signatures and check for tampering
Check token expiration, issued at, and not before timestamps
Verify standard JWT claims and custom application claims
Identify signing algorithms and check for weak configurations
Detect common JWT vulnerabilities and misconfigurations
Analyze token lifetime and temporal relationships
Comprehensive debugging information for developers
Debug JWT Token
Paste your JWT token to decode, validate, and analyze its contents
Signature Verification
Verify JWT token signature with secret key or public key (optional)
Privacy & Security
We do NOT store or log any JWT tokens. All analysis happens locally in your browser.
All JWT analysis happens in your browser - tokens never leave your computer.
We do not track your analysis requests or collect personal information.
Get immediate results without any server processing delays.
JWT Security Best Practices
Prefer RS256 over HS256. Never use "none" algorithm in production.
Use short-lived tokens (15-30 minutes) and implement refresh tokens.
Always validate issuer, audience, and expiration claims.
JWT Token Reference Guide
FAQ
Is JWT Token Debugger encryption?
No. It is primarily an analysis/encoding utility. If you need confidentiality, use a real encryption scheme and manage keys properly.
What should I do if the input fails to decode/parse?
Start by checking for missing padding, wrong alphabet/variant, or extra whitespace. If the data looks multi-layered, try decoding step-by-step (e.g., URL decode → Base64 decode).
Is it safe to paste sensitive data here?
For best security, avoid pasting real secrets (private keys, live tokens, seed phrases). Use test data or work offline, especially for anything that could grant access or move funds.