We use Dropwizard because it pulls together stable, mature libraries that most Java web engineers will be familiar with. It has out of the box support for sophisticated configuration, application metrics, logging and operational tools.
We use TeamCity because it allows us to #automate our #ContinuousIntegration and deployment pipelines. We can focus on delivery and quality and eliminate as many manual tasks as possible.
We use JavaScript because it allows for us create dynamic and rich user interfaces, using the latest ES6 specification. There is a great JavaScript community and pool of talented engineers.
We use Node.js because it is a really powerful Javascript runtime for building network applications. There is a large ecosystem of tools and packages available to help engineers build effective solutions to their problems . We have built robust and flexible server and client side solutions using Javascript and Node.js.
We use React because we can build complex user interfaces through composition of stateful components. It allows us to build UIs faster, through component reuse and there is a wide range of community maintained components available to build upon. React components are easily testable which gives us an assurance of quality.
We use Kubernetes because it makes managing complex Docker-based deployments easy. It has great documentation and user interface and it also makes rolling releases extremely easy.
We use Kubernetes because it makes managing complex Docker-based deployments easy and supports features like auto-scaling and so on. It is also great for rolling deployments.
We use Selenium because it allows our QA engineers to develop automated and reproducible tests. It helps avoid regressions and keeping our tools bug free.
We use Python because it makes prototyping very easy. It requires people to write clean code from the very start. It is also the top language of choice for people in data science with some great libraries, which we take advantage of.
We use Hadoop because it allows us to process and store vast amounts of data, which comes in at very high rates too! The whole ecosystem is very well maintained and documented and it suits our needs very well.