Decode and inspect JSON Web Tokens — your token never leaves your browser.
JWT Decoder is a free online tool that decodes and inspects JSON Web Tokens (JWTs) instantly. Paste any JWT and see the decoded header, payload, claims, expiration time, and signature information in a clear, formatted view. JWTs are the standard authentication mechanism for modern web applications and APIs. They consist of three Base64-encoded parts: header (algorithm and token type), payload (claims and user data), and signature (verification). This tool decodes the first two parts and displays them in a readable format. Understanding the contents of a JWT is essential for debugging authentication issues, verifying token claims, checking expiration times, and auditing access tokens. This tool makes JWT inspection fast and visual without needing command-line tools. Everything runs entirely in your browser. Your tokens are never sent to any server — this is critical for JWTs which often contain sensitive user data, permissions, and session information. There are no usage limits and no account required. Common use cases include debugging OAuth flows, verifying API authentication tokens, checking token expiration before deployment, auditing access permissions in JWT claims, and understanding third-party authentication integrations.