# Performance for a content-driven web app frontend

Performance refers to your web application's efficiency, speed, and
responsiveness. Slow load times and inactivity lead to high bounce rates and few
conversions. Therefore, content-driven application development must prioritize
performance to make sure that users can interact with the application smoothly
and efficiently. A web application's speed and responsiveness are valued across
industries; news applications are expected to provide articles as fast as
possible, ecommerce applications must load products quickly to keep potential
customers interested, and documentation or blogs demand quick loading for clear
navigation and reader satisfaction.

Tools for assessing the performance of content-driven applications include:

- [PageSpeed Insights (PSI)](https://pagespeed.web.dev/): Run by web.dev is a tool to check the experience of mobile and desktop and provide suggestions on what to improve. This is powered by the Chrome User Experience Report (CrUX) dataset and checks for multiple types of experiences.
- [Lighthouse](https://developer.chrome.com/en/docs/lighthouse/): Can be found in [Google Chrome Developer
  Tools](https://github.com/GoogleChrome/lighthouse) and has a [browser
  extension](https://chrome.google.com/webstore/detail/lighthouse/blipmdconlkpinefehnmjammfjpmpbjk) to measure many aspects of the web application such as performance, accessibility, best practices, SEO and PWA audits.

The [Core Web Vitals](https://web.dev/vitals/) tool includes the
following aspects, among others:

- [Largest Contentful Paint (LCP)](https://web.dev/lcp/): measures loading performance. LCP should occur within 2.5 seconds of when the page first starts loading.
- [First Input Delay (FID)](https://web.dev/fid/): measures interactivity. Pages should have a FID of 100 milliseconds or less.
- [Cumulative Layout Shift (CLS)](https://web.dev/cls/): measures visual stability. Pages should maintain a CLS of 0.1. or less.