5 Security Mistakes Every Developer Makes (And How to Fix Them in 2026)

We all make security mistakes. The difference between a good developer and a great one is catching them before they reach production.

Here are 5 security mistakes I see in almost every codebase and how to fix them.

1. Hardcoded Secrets

The mistake: You put an API key, database password, or token directly in your source code. It works locally. You forget to remove it before committing.

The fix: Use environment variables. Every platform Vercel, Render, DigitalOcean, AWS provides secure environment variable storage. Use it. Never commit secrets.