Web

The best way to figure out how overhead impacts you is to measure it yourself. Follow along as we show you how we went about measuring overhead on Sentry and how you can measure it on your own applications.

With over 700 pull requests a month, making sure Sentry's test suite runs quicky is extremely important. This post will talk about our journey converting our component tests from Enzyme to React Testing Library that took almost 18 months, 17 engineers and almost 5000 tests.

Developers started to notice just how big our JavaScript package was and yeah, we knew. We weren’t ignoring the issues; after all, we don’t want the Sentry package to be the cause of a slowdown. But to reduce our JavaScript SDK package size effectively we had to account for shipping new capabilities, like being able to manage the health of a release and performance monitoring, while maintaining a manageable bundle size. After all, new features == bigger package - usually.

SDKs naturally increase in size over time. After all, it does take more bytes to implement more features. This is not a big deal for most languages—the relative size of each new feature is small, and load times and storage aren’t big concerns for code running on a server. Larger JS bundles mean longer load times, which in turn increase user misery, which then can cause the user to leave pages entirely.

In today’s modern web stack it’s anything but. Full stack developers are expected to write JavaScript executing in the browser, interop with multiple database technologies, and deploy server side code on different server architectures (e.g. serverless). Without the right tools, understanding how a user interaction in the browser cascades into a 500 server error deep in your server stack is nigh-impossible. Enter: distributed tracing.

Recently, Sentry converted 100% of its frontend React codebase from JavaScript to TypeScript. This year-long effort spanned over a dozen members of the engineering team, 1,100 files, and 95,000 lines of code. In this blog post, we share our process, techniques, challenges, and ultimately, what we learned along this journey.