Security is not someone else s job. Every line of code you write is a potential attack surface. The good news is that most vulnerabilities come from a small set of well-known mistakes — and they are all preventable.
The OWASP Top Ten
Injection, broken authentication, sensitive data exposure, XML external entities, broken access control — the OWASP Top Ten has been the standard checklist for web security for over two decades. If you have not read it recently, take an hour and review the latest version.
Practical Steps
Parameterize your queries. Hash your passwords with bcrypt or argon2. Validate input on the server, never trust the client. Set security headers. Keep dependencies updated. Use HTTPS everywhere. These are not advanced techniques — they are the baseline.
The best time to think about security is before you write the code. The second best time is right now.