Security breaches are expensive—averaging $4.45 million per incident in 2023. Yet many development teams treat security as an afterthought. This guide covers essential security practices that should be built into every web application from day one.
Authentication and Authorization
Never build authentication from scratch. Use proven solutions like Auth0, Firebase Auth, or AWS Cognito. Implement multi-factor authentication (MFA) for all admin accounts. Use OAuth 2.0 and OpenID Connect for third-party integrations. Enforce strong password policies and regular rotation.
- Minimum 12-character passwords with complexity requirements
- Implement rate limiting on login attempts (max 5 failures per 15 minutes)
- Use bcrypt or Argon2 for password hashing, never MD5 or SHA1
- Store refresh tokens securely, never in localStorage
Data Protection and Encryption
Encrypt data at rest using AES-256. Use TLS 1.3 for data in transit. Never store sensitive data in logs or error messages. Implement proper key management using services like AWS KMS. Regularly rotate encryption keys and monitor access to encrypted data.
API Security
Validate all inputs on the server side, never trust client-side validation. Implement proper CORS policies. Use API keys with rate limiting. Sanitize all database queries to prevent SQL injection. Never expose internal error details to clients.
Security is not a feature you add at the end—it's a foundation you build from the start.
Common Vulnerabilities to Prevent
Follow the OWASP Top 10. Prevent SQL injection with parameterized queries. Stop XSS attacks with proper output encoding. Prevent CSRF with tokens. Avoid broken authentication with secure session management. Protect against insecure deserialization. Implement proper logging and monitoring.
Security Checklist
Before launching any application: Run automated security scans (Snyk, SonarQube). Conduct penetration testing. Implement Web Application Firewall (WAF). Set up security monitoring and alerts. Create incident response plan. Train development team on security best practices. Conduct regular security audits.