tl;dr:Ruby discusses key improvements include virtualizing the server list to reduce memory usage, optimizing chat performance for smoother scrolling, and rebuilding the emoji picker natively to prevent blank frames. They also enhanced animated emoji rendering with WebP and eliminated “blanking” issues in lists.
tl;dr:Discord utilizes a Python monolith to power its API, from sending messages to managing subscriptions. To support this, they use pytest to write and run unit tests. Over the last 8 years, the time it takes to run a single test has continuously grown until it reached a point where it takes 13 seconds to run a single test. even if the test ends up doing absolutely nothing. This post discusses how tests were sped up.