We have engaged AB4 Systems to build us an IT system for accounting purposes, namely for calculation of expected credit loss under IFRS9. The final product proved to work flawlessly, with little to none bugs which helped us to finish in advance of the deadline. What I liked most during our collaboration is that the team came with their own ideas to improve the application workflow and its "feel". It was visible that the team spent time to actually understand the product, not only from a technical perspective, but also from a business point of view.They kept us informed at each stage and we had a very good symbiosis. Their availability for our last-minute changes was amazing !We will definitely recommend them for future work !