Security is not a feature you add later. It is a foundation you build from day one. Here is our production checklist. By David Friedman , Founder of AppBrewers We have audited 20+ web apps for security. The same vulnerabilities appear repeatedly. Here is the checklist we use for every project. Authentication [ ] Use OAuth 2.0 / OpenID Connect (Firebase Auth, Clerk, Auth0) [ ] Enforce strong passwords (8+ chars, complexity requirements) [ ] Implement brute-force protection (rate limiting) [ ] Use secure session tokens (HTTPOnly, SameSite, Secure flags) [ ] Add multi-factor authentication for admin roles Authorization [ ] Verify permissions on every API endpoint (server-side) [ ] Use Role-Based Access Control (RBAC) or Attribute-Based Access Control (ABAC) [ ] Never trust client-side permission checks [ ] Validate resource ownership (user A cannot access user B's data) Data Protection [ ] Encrypt data at rest (AES-256) [ ] Encrypt data in transit (TLS 1.3 minimum) [ ] Hash passwords with bcrypt / Argon2 (never…