Crystal 0.31.0 release comes with multi-threading preview, changes in numbers, performance improvements and as usual fixes and improvements in across the std-lib. There are 191 commits since 0.30.1 by 23 contributors.
Service objects for Crystal, aka Agents. Crystal provides primitives for achieving concurrent applications, but doesn't have advanced layers for structuring applications. Earl tries to fill that gap with a simple object-based API that's easy to grasp and understand.
Invidious is an alternative front-end to Youtube with a lot of awesome features such as audio-only mode and no ads. Its' backend is written in Crystal using Kemal.