AuthenticationSecurityJWT
The Complete Guide to SaaS Authentication in 2026
Firas Sayah·April 1, 2026·6 min read
Authentication Done Right
Every SaaS needs authentication, but most tutorials only cover the basics. Here's the complete picture.
JWT with Refresh Tokens
Access tokens should be short-lived (15 minutes). Refresh tokens handle re-authentication silently:
- User logs in → receives access token (15m) + refresh token (7d)
- Access token expires → frontend calls /auth/refresh
- Server verifies refresh token → issues new pair
- Refresh token is rotated and old one is invalidated
Google OAuth
Social login reduces friction. With Passport.js and NestJS:
Cloudrix SaaS Starter ships with this pre-configured and tested.
Skip weeks of boilerplate — auth, payments, multi-tenancy, and deployment included out of the box.
Try the live demo →- User clicks "Sign in with Google"
- Redirected to Google consent screen
- Google redirects back with profile data
- Server creates/links account and issues JWT
Magic Links
Passwordless login via email:
- User enters email → server generates a time-limited token
- Email sent with login link
- User clicks link → token verified → JWT issued
- Token expires after 10 minutes, single use
Two-Factor Authentication (2FA)
TOTP-based 2FA with backup codes:
- User scans QR code with authenticator app
- 6-digit code rotates every 30 seconds
- 8 backup codes generated for recovery
- 2FA enforced at login — not just enabled
Our Implementation
All of these patterns are fully implemented in SaaS Starter, with proper error handling, rate limiting, and security headers. Explore the full authentication feature to see how JWT, OAuth, 2FA, and magic links work together.