Glossary · Websites and content systems
Web performance
How quickly and reliably a website loads, renders, responds, and remains stable for real visitors.
Also called: website performance, page speed
Definition
Web performance covers network delivery, file size, caching, rendering, interaction responsiveness, layout stability, runtime work, and the conditions of real devices and connections.
Why it matters
Slow or unstable pages create friction in discovery, evaluation, and conversion and can be especially costly on mobile connections.
Common misunderstanding
One laboratory score is evidence, not a complete picture of performance for every user and page.
Related terms
Related system family: Websites & Publishing
Sources
- Web performance (opens in a new tab) · MDN Web Docs
Last reviewed July 16, 2026