# JWT Decoder & Claims Inspector — Auth Platform Guides, Language Guides, Use-Case Guides, Definitions

For the full tool, see: [https://capytoolkit.com/tools/developer/jwt-decoder/](https://capytoolkit.com/tools/developer/jwt-decoder/)

## JWT Decoder & Claims Inspector: Code Examples
[Auth0 JWT Format and Claims](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#auth0-jwt-format): Auth0 JWT claim structure: sub, aud, azp, iss patterns, ID token vs access token differences. Decode Auth0 JWTs entirely offline.
[Firebase JWT and Custom Token Claims](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#firebase-custom-tokens): Firebase ID token and custom token claim structure. uid, firebase claim, sign_in_provider, service account signing. Decode offline.
[Google OAuth ID Token and Service Account JWT Claims](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#google-oauth-jwt): Google OAuth ID token structure: iss, hd, sub, email, service account JWT format. Decode and inspect Google JWTs entirely offline.
[Keycloak JWT Claims and Role Structure](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#keycloak-jwt-claims): Keycloak access token structure: realm_access and resource_access roles, iss format, preferred_username. Decode Keycloak JWTs offline.
[Auth0 sub Claim Format and Connection Prefixes](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#auth0-sub-claim-format): Auth0 sub claim format: connection-type prefix, provider user ID structure, google-oauth2, auth0, github patterns. Decode Auth0 tokens offline.
[AWS Cognito JWT Claims and Token Types](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#aws-cognito-jwt): AWS Cognito JWT structure: ID token vs access token, token_use claim, cognito:groups, cognito:username, JWKS endpoint. Decode Cognito JWTs offline.
[Okta JWT Claims and Access Token Structure](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#okta-jwt): Okta JWT claim structure: scp, uid, ver, groups, iss format, JWKS endpoint. Decode and inspect Okta access tokens and ID tokens offline.
[Azure AD JWT Claims and Microsoft Entra ID Tokens](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#azure-ad-jwt): Azure AD / Microsoft Entra ID JWT structure: tid, oid, scp, roles claims, v2.0 endpoint, JWKS location. Decode Azure AD tokens offline.
[Supabase Auth JWT Claims and Row-Level Security](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#supabase-jwt): Supabase Auth JWT structure: role claim, aal (authentication assurance level), session_id, app_metadata vs user_metadata. Decode Supabase tokens offline.
[Clerk JWT Token Format and Session Claims](https://capytoolkit.com/tools/developer/jwt-decoder/code-examples/#clerk-jwt): Clerk JWT structure: session tokens, M2M tokens, azp claim, sub as user ID, JWT Templates for custom claims. Decode Clerk tokens offline.

## Language Guides
[Using a JWT Inspector: Read Any Token Instantly](https://capytoolkit.com/tools/developer/jwt-decoder/jwt-inspector/): JWT inspector: read JWT headers, payloads, and expiry offline in your browser. No server required. Inspect any token from any provider safely.
[Decode a JWT in Python with PyJWT](https://capytoolkit.com/tools/developer/jwt-decoder/decode-jwt-python/): Decode JWT tokens in Python using PyJWT 2.13.0. Read header and payload without signature verification. Full decode with JWKS using cryptography extra.
[Decode a JWT in JavaScript and Node.js](https://capytoolkit.com/tools/developer/jwt-decoder/decode-jwt-javascript/): Decode JWT tokens in JavaScript with jose (browser/ESM) and jsonwebtoken (Node.js). Read header and payload without verification. Code examples.
[Decode a JWT in Java with JJWT](https://capytoolkit.com/tools/developer/jwt-decoder/decode-jwt-java/): Decode JWT tokens in Java using JJWT (io.jsonwebtoken). Read payload without verification and perform full verified decode. Maven and Gradle examples.
[Decode a JWT in C# / .NET](https://capytoolkit.com/tools/developer/jwt-decoder/decode-jwt-csharp/): Decode JWT tokens in C# using JwtSecurityTokenHandler and JwtSecurityToken. Read claims without verification and with full validation. .NET code examples.
[Decode a JWT in Go](https://capytoolkit.com/tools/developer/jwt-decoder/decode-jwt-golang/): Decode JWT tokens in Go using github.com/golang-jwt/jwt/v5. ParseUnverified for inspection, ParseWithClaims for verification. MapClaims and struct examples.

## Guides
[Debugging JWT Expiry and Clock Skew Errors](https://capytoolkit.com/tools/developer/jwt-decoder/jwt-expiry-debugging/): Debug JWT expiry errors: exp timestamp format, clock skew, nbf claim, iat interpretation. Paste your token above to read the exact expiry time.
[Fixing JWT Invalid Signature Errors](https://capytoolkit.com/tools/developer/jwt-decoder/jwt-invalid-signature/): Debug JWT invalid signature errors: wrong secret, algorithm mismatch, token mutation, multi-tenant key selection. Read the token header to diagnose.
[HS256 vs RS256: Choosing a JWT Signing Algorithm](https://capytoolkit.com/tools/developer/jwt-decoder/hs256-vs-rs256/): HS256 vs RS256 vs ES256: symmetric vs asymmetric JWT signing, security tradeoffs, use cases, algorithm confusion attacks. Choose the right algorithm.
[Decode Your JWT's Standard Claims Above](https://capytoolkit.com/tools/developer/jwt-decoder/jwt-claims-reference/): Paste any token into the decoder above to see which of the seven registered claims (iss, sub, aud, exp, nbf, iat, jti) it actually carries, then check each one against its RFC 7519 definition.
[JWT Access Token vs Refresh Token Patterns](https://capytoolkit.com/tools/developer/jwt-decoder/jwt-refresh-token-pattern/): JWT access token and refresh token patterns: lifetimes, storage, rotation, revocation. Decode your access token above to read its exp and claims.

## JWT Decoder & Claims Inspector Reference
[What Is a JSON Web Token (JWT)?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-a-jwt): JSON Web Token definition: three-part structure, header, payload, signature, Base64Url encoding, RFC 7519. Decode any JWT instantly above.
[What Is a JWT Claim?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-a-jwt-claim): JWT claim definition: registered claims (iss, sub, aud, exp), private claims, public claims, RFC 7519 namespacing rules. Read any token's claims above.
[What Is a JWKS (JSON Web Key Set)?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-jwks): JWKS definition: JSON Web Key Set format, kid, n, e fields, key rotation, discovery endpoint. Fetch JWKS to verify JWT signatures from any provider.
[What Is the JWT iss Claim?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-jwt-iss-claim): JWT iss claim definition: issuer identifier format, validation rules, multi-tenant security, cross-issuer acceptance prevention. Decode your token above.
[What Is the JWT sub Claim?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-jwt-sub-claim): JWT sub claim definition: subject identifier, stability guarantee, database primary key use, provider sub formats. Decode your token above.
[What Is the JWT exp Claim?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-jwt-exp-claim): JWT exp claim definition: Unix timestamp in seconds, expiry validation, clock skew, NumericDate format. Decode your token above to read its expiry.
[What Is the JWT aud Claim?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-jwt-aud-claim): JWT aud claim definition: audience validation, API identifier format, string vs array, multi-audience tokens, cross-service misuse prevention.
[What Is a Bearer Token?](https://capytoolkit.com/tools/developer/jwt-decoder/reference/#what-is-bearer-token): Bearer token definition: HTTP Authorization header format, relationship to JWT, security implications, HTTPS requirement. Decode any bearer token above.