Essential PHP Backend Best Practices for Clean, Secure, and High‑Performance Code

Replace deprecated mysql_ functions – PHP 7 removed them; migrate to mysqli_ or PDO for safer database interactions.

Avoid garbage code – Write clear, maintainable code; PHP 7’s speed can mask inefficiencies.

Load scripts wisely and use caching – Load only needed scripts, combine where possible, write efficient queries, and leverage caching mechanisms.

Omit the closing PHP tag – Leaving out the final ?> prevents accidental whitespace output and aligns with modern standards.

Minimize reference passing – Unnecessary references make code harder to understand; functions like shuffle() and sort() modify arrays in place, which can be confusing.

Avoid queries inside loops – Run queries outside loops, build result sets in memory, and iterate over them; this reduces database load and improves performance.

Be selective with SQL wildcards – Specify required columns instead of using * to reduce resource usage and improve clarity.

Validate and sanitize user input – Always filter, escape, or use prepared statements (e.g., filter_var()) to protect against malformed or malicious data.

Prioritize readability over cleverness – Write elegant, self‑documenting code; prefer clear variable names and OOP structures over terse, obscure tricks.

Leverage existing libraries – Use Composer, Packagist, and community packages instead of reinventing functionality.

Adopt modern development tools – Employ logging, profiling, unit testing, and UI frameworks (e.g., Bootstrap) to streamline development.

Broaden language knowledge – Complement PHP skills with HTML, CSS, JavaScript, and MySQL; then explore OOP PHP, JavaScript, and other languages such as Ruby, Java, C#, Android, iOS, and Windows Phone.