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Best Practices

Best Practices & Guidelines

Security, performance, code quality, accessibility, and futureproofing strategies

CRITICAL

Input Validation & Sanitization

Always validate and sanitize user input to prevent injection attacks

Practices:

  • Validate all user inputs on both client and server side
  • Use schema validation libraries like Zod or Yup
  • Sanitize HTML input to prevent XSS attacks
  • Use parameterized queries to prevent SQL injection
  • Implement rate limiting on API endpoints
  • Never trust client-side validation alone

Recommended Tools:

ZodYupDOMPurifyexpress-validator
CRITICAL

Authentication & Authorization

Implement secure authentication and authorization mechanisms

Practices:

  • Use established auth libraries (Clerk, NextAuth, Auth0)
  • Implement proper session management
  • Use secure, httpOnly cookies for session tokens
  • Implement multi-factor authentication (MFA) for sensitive operations
  • Hash passwords with bcrypt or argon2
  • Implement proper password policies
  • Use JWT tokens securely (short expiry, refresh tokens)
  • Implement role-based access control (RBAC)
  • Never store sensitive data in localStorage

Recommended Tools:

ClerkNextAuth.jsAuth0Luciabcryptjose
CRITICAL

Environment Variables & Secrets

Secure management of sensitive configuration and secrets

Practices:

  • Never commit .env files to version control
  • Use .env.example to document required variables
  • Validate required environment variables on startup
  • Use secret management services for production (Vercel, Railway, AWS Secrets Manager)
  • Prefix client-side env vars (e.g., NEXT_PUBLIC_*)
  • Rotate API keys and secrets regularly
  • Use different credentials for different environments

Recommended Tools:

dotenvVercelRailwayAWS Secrets Manager
CRITICAL

HTTPS & Secure Communication

Ensure all communication is encrypted

Practices:

  • Always use HTTPS in production
  • Implement HSTS (HTTP Strict Transport Security)
  • Use secure WebSocket connections (wss://)
  • Implement Content Security Policy (CSP)
  • Set proper CORS policies
  • Use secure cookies (Secure, HttpOnly, SameSite flags)

Recommended Tools:

Let's EncryptCloudflareVercel (automatic HTTPS)
HIGH

Dependency Security

Keep dependencies secure and up-to-date

Practices:

  • Regularly audit dependencies (npm audit, pnpm audit)
  • Keep dependencies updated
  • Review dependency licenses
  • Use lock files (package-lock.json, pnpm-lock.yaml)
  • Minimize dependencies
  • Use tools like Snyk or Dependabot
  • Review code of critical dependencies

Recommended Tools:

npm auditSnykDependabotSocket.dev
HIGH

API Security

Secure your API endpoints

Practices:

  • Implement rate limiting
  • Use API keys for authentication
  • Validate request body schemas
  • Implement proper error handling (don't expose stack traces)
  • Use CORS appropriately
  • Implement request size limits
  • Log security events
  • Use API versioning

Recommended Tools:

express-rate-limitZodHelmet.jscors
CRITICAL

XSS Prevention

Prevent Cross-Site Scripting attacks

Practices:

  • Sanitize user-generated content
  • Use frameworks that auto-escape (React, Vue)
  • Set Content Security Policy headers
  • Validate and sanitize URLs
  • Use textContent instead of innerHTML when possible
  • Implement proper input validation

Recommended Tools:

DOMPurifyReact (auto-escaping)CSP headers
HIGH

CSRF Protection

Prevent Cross-Site Request Forgery attacks

Practices:

  • Use CSRF tokens for state-changing operations
  • Implement SameSite cookie attribute
  • Verify Origin and Referer headers
  • Use modern frameworks with built-in protection
  • Require re-authentication for sensitive operations

Recommended Tools:

csurfNext.js (built-in)SameSite cookies
HIGH

Data Privacy & GDPR

Respect user privacy and comply with regulations

Practices:

  • Implement cookie consent
  • Provide privacy policy
  • Allow users to delete their data
  • Encrypt sensitive data at rest
  • Implement data retention policies
  • Use privacy-focused analytics
  • Anonymize user data when possible

Recommended Tools:

Plausible AnalyticsPostHogcookie consent libraries

Important Note

These best practices should be adapted to your specific use case and requirements. Always test thoroughly and consider your application's unique security, performance, and accessibility needs.