Implementing secure authentication in a modern single-page or server-rendered application is fraught with security pitfalls. The age-old debate of JWTs in LocalStorage versus HTTP-only Session Cookies continues, but the consensus has largely settled on HTTP-only cookies as the primary defense against Cross-Site Scripting (XSS) attacks.
OAuth2 and social logins have become the standard expectation for consumer applications, removing the friction of password creation. For enterprise SaaS, SAML and Single Sign-On (SSO) are table stakes. Passkeys and biometric authentication are rapidly gaining adoption, offering a future where passwords are entirely obsolete, immune to phishing, and far more convenient for users.
When building a custom authentication flow, it is highly recommended to leverage established identity providers like Supabase Auth, Clerk, or Auth0 rather than rolling your own crypto. Authentication is a solved problem, and the risks of a homegrown implementation vulnerabilities far outweigh the benefits of minor customizations.