Hi! 👋 I'm Max Rozen.

I'm also known as rozenmd around the internet. I'm an ex-Atlassian, and these days I work at Cloudflare, helping build D1.

I run OnlineOrNot, a service that provides status pages and uptime monitoring for websites, APIs, and cron jobs.

I also run this blog on the side, 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 mastodon are your best bets.

I'm also on twitter.