Our first experience with .NET core was when we developed our OSS feature management platform - Tweek (https://github.com/soluto/tweek). We wanted to create a solution that is able to run anywhere (super important for OSS), has excellent performance characteristics and can fit in a multi-container architecture. We decided to implement our rule engine processor in F# , our main service was implemented in C# and other components were built using JavaScript / TypeScript and Go.

Visual Studio Code worked really well for us as well, it worked well with all our polyglot services and the .Net core integration had great cross-platform developer experience (to be fair, F# was a bit trickier) - actually, each of our team members used a different OS (Ubuntu, macos, windows). Our production deployment ran for a time on Docker Swarm until we've decided to adopt Kubernetes with almost seamless migration process.

After our positive experience of running .Net core workloads in containers and developing Tweek's .Net services on non-windows machines, C# had gained back some of its popularity (originally lost to Node.js), and other teams have been using it for developing microservices, k8s sidecars (like https://github.com/Soluto/airbag), cli tools, serverless functions and other projects...

I've used .NET for many years, but only in recent years, after Microsoft introduced .NET Core, I've found a new love and excitement for the technology again. The main driver for us using .NET Core is not that it is cross platform compatible, open source or blazingly fast (which it is!), but the fact that we can use (what we consider) the best programming languages (mainly F# and C#) to carry out our jobs without sacrificing the other benefits.

Today we run most of our web infrastructure on .NET Core in Docker containers, deployed into a Kubernetes cluster which spans across multiple time zones in the Google Cloud and we couldn't be happier. Due to the portability of the .NET Core platform we are even able to develop many new services as serverless functions with F# which has become an absolute game changer.

Some may wonder why did we choose Grails ? Really good question :) We spent quite some time to evaluate what framework to go with and the battle was between Play Scala and Grails ( Groovy ). We have enough experience with both and, to be honest, I absolutely in love with Scala; however, the tipping point for us was the potential speed of development. Grails allows much faster development pace than Play , and as of right now this is the most important parameter. We might convert later though. Also, worth mentioning, by default Grails comes with Gradle as a build tool, so why change?