We use our own self-hosted GitLab instance to store our source code repositories.
For Java/Kotlin/Backend related work, IntelliJ is our current IDE of choice.
Slack is our main tool for companywide discussion and sharing.
We use Kotlin both in our Android App and increasingly in our polyglot backend services.
Most of our backend services are based on JAX-RS REST APIs and services written in Java. Our information extraction and document analysis framework is also written in Java.
MongoDB is used to store most of our data, both user-related (e.g. documents, contacts etc.) and global.
All our backend services are containerized using Docker.
All our source code lives in git repositories, and we make heavy use of feature branches, a pull request and code review based workflow.
Akka powers our asynchronous document upload processor, handling e.g. tasks for OCR, thumbnail generation and document analysis.
Our own ElasticSearch cluster is used to provide fast fulltext search through all your documents and digitalized paperwork.
Our main web application is built on Aurelia and GWT.
We use J2Objc and GWT to provide a shared library of cross-platform code that is used on all our client platforms (Android, iOS and the web) and even in the backend.