What security practices are essential in backend and API development?

Essential backend security practices begin with input validation and sanitization on every API endpoint: never trust data sent from the client, and validate format, type, length, and allowable values before processing. Parameterized queries or an ORM must be used for all database interactions to prevent SQL injection, which remains one of the most common and damaging web vulnerabilities per the OWASP Top 10.

Authentication must use industry-standard protocols: JWT (JSON Web Tokens) for stateless API authentication, OAuth 2.0 for third-party service authorization, and bcrypt or Argon2 for password hashing. API rate limiting prevents brute force and denial-of-service attacks. All API traffic must be served over HTTPS with TLS 1.2 or higher. Secrets management using tools like AWS Secrets Manager or HashiCorp Vault ensures credentials are never hardcoded in source code. Dependency scanning using Snyk or OWASP Dependency-Check identifies vulnerable libraries before they reach production.