Hi! 👋 I'm Max Rozen. I'm also known as rozenmd around the internet.

I run OnlineOrNot on the side, an Incident Management service that provides uptime monitoring, extremely performant status pages, and more.

These days I work at Cloudflare, helping build wrangler2.

I also run this blog, where I write about React, and provide advice that hopefully helps improve your career as a frontend developer.

If you read something here and like it, feel free to share it and let me know!

Table of Contents


  • useEffect By Example
    • Get the hang of using useEffect like a pro, with useEffect By Example.
    • You'll learn how to use useEffect to fetch data, and avoid pesky race conditions. Take the guesswork out of using the dependency array, and prevent infinite re-renders through the use of useCallback and useMemo, while also keeping ESLint happy.
  • The Beginner's Guide to React Testing
    • Do you find yourself asking these questions when it comes to testing in React?
      • How do I get started testing?
      • What are all the React testing tools and how do I use them?
      • Which testing framework should I use (Enzyme or React Testing Library)?
      • What are the different types of tests we use in React?
      • How do I make testing a habit? What's a good level of test coverage?
      • Should I be doing test-driven development (TDD)?
    • If so, then this guide is for you.


Bootstrapping OnlineOrNot

Greatest hits

Year in review


If you'd like to get in touch with me, email and twitter are your best bets.