Recent content on Mark's Dev Blog
Introduction Hopefully you've already read Part 1: Fears, Opinions, and Mental Journey so you understand how I ended up with this mindset and approach. Or maybe you saw how long it was and just immediately bailed out :) Welcome either way. Part 1 was the braindump. Story, thoughts, feelings. Here's the part that probably more of you are interested in :) What my actual agent setup and dev workflow…
Introduction This post will be tough to write. There's a lot of discourse and arguing about AI everywhere you look. I've read it all. I don't want to get caught up in arguments, get misinterpreted, or be labeled with beliefs that don't apply. I am not e/acc or P(doom). I am a software engineer, I am a person, trying to figure this out same as everyone else. I am not trying to sell anything, change…
I've spent years explaining the basics and nuances of React's rendering behavior . That post is by far the most widely read resource I've ever published, and it's helped thousands of React devs actually understand how React rendering actually works. Now, we have the React Compiler , which promises to "automatically optimize your React apps". But how does it work? What is it doing to your…
I've spent a lot of time debugging and doing performance optimization investigations throughout my career. It's second nature to me at this point, but a lot of developers have never really tried to investigate app performance. In late 2025 I spent multiple months investigating and optimizing performance in the Immer immutable update library. This talk covers how to approach performance…
I spend a lot of time reading (and participating in) discussions in the React community, across many different sites. Over the last few years I've seen an increasing amount of frustration and concerns from the community, questions about the motivations and intent behind React's development, and a growing disconnect between how the React team wants React to be used, and how the ecosystem is using…
Introduction Today, the state of React and its ecosystem is complicated and fractured, with a mixture of successes, skepticism, and contention. On the positive side: React is the most widely used UI framework, and its concepts have influenced the rest of the JS ecosystem. The React team recently released React 19 after multiple years of development. This was a huge release, including official…
The main thesis of this talk is that maintainers do a lot more than just write features and fix bugs, and that really most of what we do involves thinking about and interacting with the users of our library. That includes answering support questions, writing docs, thinking about how versioning and backwards compatibility will impact people, and a lot more. Hopefully this proves useful to other…
My remote presentation for React Advanced 2024 was on "Designing Effective Documentation: Lessons Learned Writing the Redux Docs". I've spent a lot of my time working on the Redux docs, and it is in fact how I got my start working on Redux! . Hopefully this proves useful to other folks writing docs for tools and libraries. Designing Effective Documentation - video And here's the slides: Designing…
I had the chance to speak at both React Connection Paris in April and React Summit Amsterdam in June, and at both conferences I gave a talk on "Why Use Redux Today?". Both of those had the same core content, but I tweaked and updated the slides for React Summit. Why Use Redux Today? - video and the earlier livestream: Why Use Redux Today? - livestream And here's the slides: Why Use Redux Today? -…
I gave a lightning talk at React Summit US, and did a quick run-through of what's changing in RTK 2.0. I've linked the livestream at the right timestamp for now, and will link the final video when it's live. What's New in Redux Toolkit 2.0 - video And here's the slides: What's New in Redux Toolkit 2.0 - slides (and totally unrelated to my talk, had the chance to lead a Carnival Parade of costumed…
I work at Replay.io , and I've spent all of this year building some incredibly advanced React debugging features that make use of our time-traveling backend API. The biggest one is our React DevTools integration. Early in 2023, I wrote a post for the Replay.io blog on How We Rebuilt React DevTools with Replay Routines , which recapped the initial working version. I've spent much of this year…
My extensive post "A (Mostly) Complete Guide to React Rendering Behavior" is the most popular and widely appreciated post I've written. After the recent updates to cover React 18, it's now around 10,900 words long! I recently had a chance to give a talk based on that post for React Advanced in 2022 and React Rally in 2023. React Rally 2023 I'll link the video once it's available. A (Brief) Guide…
Table of Contents Introduction Redux Packages Background Packages and Configurations Issue History Early Attempts Migrating to Vitest Initial Alpha Testing Researching Better Configuration Setting Up CI Checks for Packaging Initial CI Setup Are The Types Wrong? Packaging Updates, Round 2 Switching Build Tooling UMD Build Artifact Changes Webpack 4 Compat Immer 10 Beta TypeScript Declarations Round…
In mid-2021 I had the chance to do a talk on "Debugging Software" for a meetup hosted by Mintbean.io. In 2022, I did an updated "Debugging JS" version of the talk for ThisDot Media's "JS Drops" video series. I previously did a post on Debugging Tips , where I listed some quick tips for thinking about debugging, and recapped the stories of several interesting bugs I ran into and solved. I later had…
I had the opportunity to talk on a number of different podcasts and interviews over the course of the year. I've gathered them here as a directory. ThisDot / Tracy Lee: How to Contribute to Redux Tracy Lee is a prolific podcaster, and her company ThisDot creates numerous shows related to the JS ecosystem. She had me on as part of a new "How to Contribute..." series, where I talked about ways to…