Last updated: August 26, 2026.
Reliable PHP code starts with explicit inputs, predictable types, secure database access, and tests around business rules.
A small service with explicit dependencies
<?php
declare(strict_types=1);
final class PriceCalculator
{
public function total(int $quantity, string $unitPrice): string
{
if ($quantity < 1 || !preg_match('/^d+.d{2}$/', $unitPrice)) {
throw new InvalidArgumentException('Invalid price input.');
}
return bcmul((string) $quantity, $unitPrice, 2);
}
}Practical habits
| Habit | Benefit |
|---|---|
| Enable strict types and use type declarations | Makes interfaces and failures clearer |
| Validate at system boundaries | Keeps invalid data out of core logic |
| Use prepared statements | Separates SQL from data |
| Keep secrets in environment-backed configuration | Avoids exposing credentials in source |
| Write automated tests for business rules | Makes refactoring safer |
| Log errors with request context, not secrets | Improves diagnosis without leaking data |
Prefer small functions, standard tooling, dependency management with Composer, and supported PHP releases. Optimize only after measuring the real bottleneck.
