More than 10 years ago e-conomic was founded on an idea to bring accounting software to the cloud for businesses. As with any other software 10 years down the road it carried a lot of legacy. Some technologies are deprecated, your understanding of scalable architecure evolves, and you start to grow faster than anyone expected.
A few years back we made a conscious choice to invest in using newer technologies and different programming languages. To create an infrastructure that would scale faster than our growth. It's a long process, and still is, but today we always strive to use the right tool for the right job and we have a ton of different services running which can be independently deployed. There is still legacy, and there are still things we wish were different - but we love challenges and we love to keep working. Open source is a big part of this process.
These are some of our own open sourced projects that we use in our stack everday (a full list can be found on github). As we move forward and gain more experience we use more and more open source ourselves and encourage our developers to contribute to other open source projects.