Site performance is the broad measure of how effectively a website operates across all technical dimensions: page load speed, server response times, uptime and reliability, database query efficiency, caching effectiveness, error rates, and Core Web Vitals scores. While the term is often used interchangeably with site speed, site performance is wider in scope — a site can load pages quickly but still have poor performance if it suffers from frequent 5xx server errors, database connection timeouts under load, or a high rate of failed form submissions. Comprehensive site performance monitoring tracks both frontend metrics (LCP, TTFB, INP, CLS) and backend health signals (PHP error rates, query execution time, memory consumption, cache hit ratio). WordPress site performance is a compounding problem: each plugin added increases the number of database queries and PHP functions executed on every page load, so performance degrades gradually as sites accumulate functionality without corresponding optimization investment.
Glossary entry
