Decode JSON Web Tokens (JWT) instantly with our free online JWT decoder tool.
View header, payload, and signature information in a human-readable format with 100% privacy protection.
Perfect for developers debugging authentication tokens and security professionals analyzing JWT structure.
Copy your JWT token from your application, API response, or authentication system. JWT tokens typically look like: xxxxx.yyyyy.zzzzz (three parts separated by dots).
Paste the JWT token into the input field on our decoder page. Make sure you're copying the complete token including all three parts.
Click 'Decode JWT Token' to instantly view the decoded header, payload, and signature information. You can toggle between formatted view and raw JSON, copy individual values, and check token validity.
Decode JWT tokens from API responses to understand user authentication and authorization information
Analyze enterprise SSO tokens to verify user identity and access permissions across systems
Decode OAuth access tokens to inspect scopes, user information, and token metadata
Debug JWT tokens used for service-to-service authentication in distributed systems
Decode JWT tokens during API development to verify user claims, debug authentication issues, and understand token structure for proper implementation
Analyze JWT tokens for security auditing, check expiration times, verify claim contents, and ensure no sensitive information is exposed inappropriately
Help users troubleshoot authentication issues by decoding their JWT tokens and identifying problems like expired tokens or invalid claims
Understand JWT token structure when integrating with third-party services, implement proper token validation, and map claims to user data
Extract and analyze JWT token contents for compliance requirements, audit user access patterns, and verify proper security practices
JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. JWTs consist of three parts separated by dots: header, payload, and signature.
The header contains metadata about the token, such as the signing algorithm (HS256, RS256) and token type (JWT). The payload contains the claims, which are statements about an entity (typically the user) and additional data. The signature is created by signing the encoded header and payload with a secret key.
JWTs are commonly used for authentication and authorization in web applications, API security, single sign-on systems, and information exchange. They are stateless, meaning the server doesn't need to store session information, making them scalable and efficient.
Assuming JWT decoding equals verification
Remember that anyone can decode a JWT - verification requires the secret key. Always verify signatures on your server before trusting token contents.
Ignoring token expiration
Always check the 'exp' (expiration) claim. Expired tokens should be rejected even if they decode properly and have valid signatures.
Storing sensitive data in JWT payload
JWT payloads are base64 encoded, not encrypted. Never store passwords, credit card numbers, or other sensitive information in JWT claims.
Not validating all required claims
Validate essential claims like 'iss' (issuer), 'aud' (audience), and 'sub' (subject) according to your security requirements.
Using weak signing algorithms
Prefer strong algorithms like RS256 or ES256 over HS256 when possible, and always use cryptographically secure keys for signing.
Yes, decoding JWT tokens is completely safe. JWT tokens are designed to be decoded by anyone - they're not encrypted, just encoded. The real security comes from the signature verification, which requires a secret key.
Decoding simply translates the base64-encoded parts into readable JSON. Verification uses a secret key to confirm the signature is valid and the token hasn't been tampered with. Our tool can only decode, not verify.
No, signature verification requires the secret key used to sign the token, which is only available on the server that created the JWT. This tool is for decoding and analysis only.
Standard claims include: iss (issuer), sub (subject), aud (audience), exp (expiration), nbf (not before), iat (issued at), and jti (JWT ID). These are registered claim names with specific meanings.
Common reasons include: Invalid format (not 3 parts separated by dots), corrupted base64 encoding, malformed JSON in header/payload, or the input isn't actually a JWT token.
JWT tokens often include an expiration time (exp claim). If the current time is past this timestamp, the token is considered expired and should not be trusted for authentication.
A valid JWT must have: correct format (3 parts), valid base64 encoding, parseable JSON in header/payload, valid signature (verified on server), and non-expired timestamp.
JWT tokens are secure when used correctly. They use strong signature algorithms, but the payload is only base64 encoded (not encrypted), so don't store sensitive data in JWT claims.
Common algorithms include HS256 (HMAC SHA-256), RS256 (RSA SHA-256), ES256 (ECDSA SHA-256), and EdDSA. The algorithm is specified in the JWT header.
Token lifetime depends on your security requirements. Common practice is 15-60 minutes for access tokens and 7-30 days for refresh tokens. Balance security with user experience.