JWT Decoder
Decode and verify JSON Web Tokens
JWT Token
Only required for signature validation (HS256 algorithm supported)
Transform and analyze JSON Web Tokens instantly with our comprehensive JWT decoder and verification tool. This essential utility for developers working with modern authentication systems provides complete JWT parsing, validation, and security analysis in a user-friendly interface that requires no technical expertise. JSON Web Tokens are the backbone of modern web security, used extensively in OAuth 2.0, OpenID Connect, and single sign-on systems.
Our JWT decoder breaks down any token into its three components: header, payload, and signature, displaying the contents in beautifully formatted JSON with syntax highlighting. The tool automatically detects token algorithms (HS256, RS256, ES256, and more) and validates structure integrity. Advanced features include signature verification using secret keys or public certificates, expiration time analysis with visual countdown timers, issuer and audience validation, and comprehensive security warnings for common vulnerabilities.
The decoder identifies potentially dangerous tokens, weak algorithms, and security best practices violations. Ideal for authentication developers debugging login flows, security engineers auditing token implementations, API developers integrating third-party services, and DevOps professionals troubleshooting SSO configurations. The tool supports all standard JWT algorithms and provides detailed explanations for each component, making it perfect for learning and professional development. Our JWT decoder processes tokens entirely in your browser, ensuring sensitive authentication data never leaves your device.