TL;DR: Load testing is not optional for production PHP applications. This guide covers two of the best modern tools, K6 and Artillery , with real scripts, PHP-specific gotchas, CI/CD integration, and a framework for interpreting results so you know exactly when your app is ready (and when it isn't). Why PHP Apps Need Load Testing PHP powers a staggering portion of the web, from WordPress blogs to enterprise Laravel APIs to high-traffic e-commerce platforms. Yet performance testing is consistently one of the most skipped steps in PHP development workflows. The consequences are predictable: a product launch doubles traffic, the database connection pool saturates, opcache fills up, and suddenly a healthy-looking application is returning 502s. Load testing answers questions your unit tests and code reviews never can: How many concurrent users can my app handle before response times degrade? Where exactly does it break, PHP-FPM, MySQL, Redis, or the application code itself?…