Authentication Strategies for Web Applications

Authentication — verifying who the user is — is foundational. Session-based, JWT, OAuth, passwordless — each has tradeoffs. Here's how to choose and implement auth for your web application.

Table of Contents

• Session-Based Auth
• JWT (Token-Based)
• OAuth & Social Login
• Passwordless (Magic Link, OTP)
• Multi-Factor Authentication
• How to Choose
• Frequently Asked Questions

Session-Based Auth

Server stores session (in memory, Redis, or DB). Client gets session ID in cookie. Server validates on each request. Simple, revocable. Use HttpOnly, Secure, SameSite cookies. Best for: traditional web apps, server-rendered.

JWT (Token-Based)

Stateless. Server signs a token (user id, expiry); client sends it (header or cookie). No server-side session store. Good for APIs, SPAs, mobile. Downsides: hard to revoke before expiry; don't store sensitive data in payload.

OAuth & Social Login

"Login with Google/GitHub" — delegate auth to provider. OAuth 2.0 flow. Reduces password management. Use for consumer apps. For B2B, add SAML/OIDC for enterprise SSO. Libraries: NextAuth, Passport, Auth0.

Passwordless (Magic Link, OTP)

No password. User enters email, gets magic link or OTP. Click or enter code to log in. Simpler UX, fewer support tickets. Use Resend, SendGrid, or Twilio. Good for internal tools, low-friction signup.

Multi-Factor Authentication

Add second factor: TOTP (Google Authenticator), SMS, or hardware key. Required for admin, finance, sensitive actions. Use speakeasy, otplib, or Auth0/Clerk for MFA.

How to Choose

• Traditional web app → Session + cookies
• SPA + API → JWT or session (httpOnly cookie)
• Consumer app → OAuth/social login
• Internal tool → Passwordless (magic link)
• Enterprise → SAML/OIDC SSO

Frequently Asked Questions