JWT Inspector
Inspect JWT headers, claims, temporal validity, algorithms, and common security issues without uploading tokens.
JWT input
JSON Web Tokens
Review JWT contents and identify common security issues
JWT inspection helps developers understand token contents, verify claim values, review algorithms, and identify common implementation mistakes before deploying authentication systems.
What this tool inspects
Review the JWT header, payload claims, expiration, issued-at time, not-before time, algorithm, issuer, audience, subject, and other registered or custom claims.
What this tool does not verify
Inspecting a JWT does not verify its signature, confirm that the signing key is trusted, or determine whether the token should be accepted by your application.
Guide
About JWT Inspector
JWT inspection goes beyond basic decoding by highlighting claim semantics, lifetime, algorithms, and common implementation risks.
This tool reviews token structure and flags conditions that may require closer validation.
Inspection does not replace cryptographic signature verification or application-specific authorization checks.
What the inspector reviews
Review header and claim fields that influence security decisions.
- Signing algorithm
- Key identifier
- Issuer and audience
- Expiration and activation
- Token lifetime
- Missing or unusual claims
Common JWT risks
Risk depends on how the application validates and uses the token.
- Accepting unexpected algorithms
- Ignoring issuer or audience
- Excessive token lifetime
- Missing expiration
- Sensitive payload data
Temporal claims
exp, nbf, and iat should be interpreted using NumericDate seconds and a defined clock-skew policy.
Inspection versus acceptance
A token should be accepted only after signature verification, claim validation, and authorization checks.
FAQ
Frequently asked questions
How is JWT Inspector different from JWT Decoder?
The inspector adds security-oriented interpretation and warnings around claims and algorithms.
Does it verify the signature?
No. Use the JWT Validator with the expected key or secret.
Is a missing exp claim always invalid?
Not universally, but many applications should require expiration based on their security policy.
Why is a long token lifetime risky?
A stolen token remains useful for longer before expiration.
Should I trust the alg header?
No. The verifier should enforce an expected algorithm independently.
Is the token uploaded?
Inspection is intended to occur locally in your browser.
Continue exploring
Related tools
Useful tools for the next step in the same workflow.
JWT Decoder
Decode JWT headers and claims locally without uploading the token.
Authentication
JWT Signature Verifier
Verify HMAC JWT signatures and important claims locally.
Authentication
JWK & JWKS Inspector
Inspect JSON Web Keys, review JWKS collections, and generate RFC 7638 thumbprints.
PKI & Certificates
Unix Timestamp Converter
Convert Unix timestamps and readable date values locally.
Encoding & Data
Website Security Scanner
Inspect HTTPS, TLS, headers, cookies, and common security configuration issues.
Website Security
SSL/TLS Checker
Inspect a live server's TLS protocol, cipher, certificate chain, expiration, and trust status.
Website Security