JWT (JSON Web Token) is a secure digital token used by websites and applications to verify user identity after login. When you sign in to an online service, the system creates a JWT containing encrypted information about your identity and permissions. This token travels with your requests, allowing the system to confirm you are authorized without checking the database each time. JWTs are commonly used in municipal online services, citizen portals, and applications requiring secure authentication. The token format is an internet standard, making it work across different systems. Understanding JWTs helps explain how modern websites keep your information secure while providing convenient access.