Frontend System Design: Performance API, Chrome, React Profiler

👉 Frontend System Design Essentials — Course: https://icodeit.thinkific.com/courses/frontend-system-design-essentials 👉 Frontend System Design Essentials — Book: https://leanpub.com/frontend-system-design-essentials/ “This page feels slow” doesn’t tell us much. How slow? Which part? Compared to what? Without a baseline, performance work is mostly guesswork — and after a change, we often don’t know whether it helped. In this video I walk through three ways I normally measure frontend performance, using the Log Analyzer demo: the Performance API, Chrome Performance, and React Profiler. Each answers a different question — so you can choose a real system design trade-off instead of optimizing at random. You'll learn: How performance.now() / mark() / measure() give a baseline How Chrome Performance shows where the browser spent time How React Profiler isolates render cost in a subtree Why measure first, then decide (Worker, virtualization, cache, …) Final takeaway: Measure first. Establish a baseline. Understand where the time goes. Then decide what to optimize — that’s frontend system design, not guesswork. 📘 MY BOOKS & COURSES 👉 Frontend System Design Essentials (Course): https://icodeit.thinkific.com/courses/frontend-system-design-essentials 👉 Frontend System Design Essentials (Book): https://leanpub.com/frontend-system-design-essentials/ 👉 React Anti-Patterns (Amazon): https://www.amazon.com/dp/1805123971 👉 More Tutorials on Advanced Patterns: https://icodeit.com.au/tutorials/advanced-network-patterns-react 📩 STAY CONNECTED 🧠 Newsletter (system design & clean code): https://juntao.substack.com 🌐 Website & Blog: https://icodeit.com.au 🐦 Twitter / X: http://twitter.com/JuntaoQiu 📺 YouTube (subscribe): https://www.youtube.com/@icodeit.juntao JetBrains has kindly provided a 20% discount for viewers of this channel. Use the code ICODEIT20 when purchasing a personal annual license from the JetBrains store. The code is valid until June 30, 2027. For transparency: JetBrains has also provided me with a complimentary All Products Pack license. There are no requirements around what I say about their tools. #frontend #systemdesign #performance #webperformance #react #chromedevtools #javascript #webdevelopment