Onedot is building an automated data preparation service using probabilistic and statistical methods including artificial intelligence (AI). From the beginning, having a stable foundation while at the same time being able to iterate quickly was very important to us. Due to the nature of compute workloads we face, the decision for a functional programming paradigm and a scalable cluster model was a no-brainer. We started playing with Apache Spark very early on, when the platform was still in its infancy. As a storage backend, we first used Cassandra, but found out that it was not the optimal choice for our workloads (lots of rather smallish datasets, data pipelines with considerable complexity, etc.). In the end, we migrated dataset storage to Amazon S3 which proved to be much more adequate to our case. In the frontend, we bet on more traditional frameworks like React/Redux.js, Blueprint and a number of common npm packages of our universe. Because of the very positive experience with Scala (in particular the ability to write things very expressively, use immutability across the board, etc.) we settled with TypeScript in the frontend. In our opinion, a very good decision. Nowadays, transpiling is a common thing, so we thought why not introduce the same type-safety and mathematical rigour to the user interface?
