Web security is not optional—it's essential. Here are the critical security practices every developer must implement.

1. Prevent SQL Injection
Always use parameterized queries or ORMs to prevent SQL injection attacks. Never concatenate user input directly into SQL queries.

2. Implement CSRF Protection
Cross-Site Request Forgery (CSRF) attacks can be devastating. Use CSRF tokens on all state-changing operations.

3. Sanitize User Input
Never trust user input. Always validate and sanitize data before processing or displaying it.

4. Use HTTPS Everywhere
Encrypt all data in transit using HTTPS. Modern browsers now flag HTTP sites as insecure.

5. Keep Dependencies Updated
Regularly update your frameworks, libraries, and dependencies to patch known vulnerabilities.

6. Implement Strong Authentication
Use strong password policies, implement multi-factor authentication, and never store passwords in plain text.

7. Set Proper Security Headers
Configure security headers like Content-Security-Policy, X-Frame-Options, and X-XSS-Protection.

By following these practices, you'll significantly reduce your application's attack surface and protect your users' data.