Microservices implemented in JavaScript running on NodeJS are becoming quite popular lately. In order to gain some experience with this, I created a little in memory NodeJS cache service. Of course statefulness complicates scalability, but if I would also have implemented a persistent store to avoid this, the scope of this blog article would have become too large. Please mind that my experience with NodeJS is limited to a NodeJS workshop from Lucas Jellema and a day of playing with NodeJS. This indicates it is quite easy to get started. In this blog I'll highlight some of the challenges I encountered and how I solved them. Also I'm shortly describing what Oracle is doing with NodeJS. Because the JavaScript world changes rapidly, you should also take into account the period between when this blog is written and when you are reading it; it will most likely quickly become outdated. You can download the code from GitHub here.