I have spent a (probably-too-big) part of my career carefully and passionately crafting Web APIs, both in .NET and Python space. In the process, I also managed to become an open-source author and maintainer somehow. Over time, I ended up collecting several valuable open source libraries and packages that have now become my every day go-to swiss-army knife of wonders. In this talk, I'll share my favorite open-source packages and show you how I use them by building a small WebAPI from scratch.