Security is not something you bolt on at the end—it's built into how you design APIs, validate input, and manage dependencies. Here are practices that should be part of your daily workflow.
Validate and Sanitize All Input
Treat every input as untrusted: query params, request bodies, headers, and file uploads. Use allowlists (not blocklists), enforce types and length limits, and never render raw user input in HTML or SQL. Parameterized queries and prepared statements prevent injection; encoding output for the right context (HTML, URL, JS) prevents XSS.
Principle of Least Privilege
Services and users should have only the permissions they need. Use short-lived credentials, avoid hardcoded secrets (use a secret manager and env vars), and scope database and API permissions narrowly. Review IAM and DB roles as part of code review.
Keep Dependencies Up to Date
Vulnerabilities in libraries are a leading cause of breaches. Pin versions in lockfiles, run automated dependency checks (e.g. Dependabot, Snyk), and have a process to patch critical issues quickly. Audit transitive dependencies too.
Log Safely, Fail Securely
Never log secrets, tokens, or full PII. Error messages to users should be generic; detailed stack traces belong in server logs only. On failure, deny access by default and avoid leaking internal state.