How do you implement authentication in Nuxt.js?

Authentication in Nuxt.js is commonly implemented using the nuxt-auth-utils or Sidebase nuxt-auth module. The pattern involves: (1) creating a server API route (e.g., server/api/auth/login.post.ts) that validates credentials and sets a secure HTTP-only cookie with a session token; (2) using useCookie or useAuthState to access the session on the client; (3) adding a global middleware in middleware/auth.global.ts that checks authentication and redirects unauthenticated users. Alternatively, nuxt-auth-utils provides setUserSession() and getUserSession() server utilities with built-in sealed cookie sessions.