Fixing web performance issues is hard. Every developer knows this experience: we insert console.log everywhere, catch some promising leads, but nothing happens before "time runs out." Eventually, the slow/buggy code never gets fixed, problems pile up on a backlog, and our end users are hurt.

We started Million to fix this. A VSCode extension that identifies slow code and suggests fixes (like ESLint, for performance!) The website is here: https://million.dev/blog/lint

I realized this was a problem when I tried to write an optimizing compiler for React in high school (src: https://github.com/aidenybai/million). It garnered a lot of interest (14K+ stars) and usage, but it didn't solve all user problems.

Traditionally, devtools either hinge on full static analysis OR runtime profiling. We found success in a mixture of the two with dynamic analysis. During compilation, we inject instrumentation where it's necessary. Here is an example:

  function App({ start }) {
    Million.capture({ start });  //  inject
    const [count, setCount] = Million.capture(useState)(start);  //  inject
 
    useEffect(
      () => {
        console.log("double: ", count * 2);
      },
      Million.capture([count]),  //  inject
    );
 
    return Million.capture(  //  inject
      <Button onClick={() => setCount(count + 1)}>{count}</Button>,
    );
  }

We are still in the very early days of experimentation! Million Lints focuses on solving unnecessary re-renders right now, and will move on to handling slow-downs arising from the React ecosystem: state managers, animations, bundle sizes, waterfalls, etc. Our eventual goal is to create a toolchain which keeps your whole web infrastructure fast, automatically - frontend to backend.

In the next few weeks, we're planning to open source (MIT) the Million Lint compiler and the VSCode extension.

To earn a living, we will charge a subscription model for customized linting. We believe this aligns our incentives with yours: we only make money when we make your app faster.

We'd love to know your thoughts – happy to answer :)