Security breaches cost enterprises an average of four million dollars per incident, and web applications remain the most common attack vector. Yet many development teams still treat security as a pre-launch checklist rather than a continuous practice woven into every stage of the development lifecycle. The practices outlined here represent the baseline that every production web application should implement, not aspirational goals.
Authentication and session management form the first line of defense. We implement authentication using battle-tested libraries rather than custom implementations, because cryptography and session management are domains where subtle bugs create catastrophic vulnerabilities. Sessions use secure, HttpOnly, SameSite cookies with short expiration windows and automatic rotation. Multi-factor authentication is mandatory for administrative access and available for all users. Password policies enforce minimum entropy rather than arbitrary complexity rules, and we integrate breach database checking to reject known-compromised passwords at registration time.
Input validation and output encoding prevent the most common vulnerability classes. Every piece of user input is validated against a strict schema on the server side, regardless of any client-side validation. We use parameterized queries exclusively to prevent SQL injection, and context-aware output encoding to prevent cross-site scripting. Content Security Policy headers restrict script execution to trusted sources. Rate limiting on authentication endpoints, API routes, and form submissions prevents brute-force attacks and abuse.
Supply chain security has become equally critical. Every dependency is a potential attack surface. We pin exact dependency versions, audit the dependency tree for known vulnerabilities on every build, and use lock files to prevent supply chain injection. Container images are built from minimal base images and scanned for vulnerabilities before deployment. Infrastructure is defined as code and deployed through audited pipelines with mandatory review gates. Secrets are stored in dedicated secret management services, never in code repositories or environment files committed to version control.