My latest project was integration REST API for one of biggest e-commerce retail. The main goal was creating an intermediate service between legacy (php, web services, sql server procs) and modern stack microservices (REST, .NET6, queues, CQRS) to stop using legacy systems in the future and start using the new ones.  I have made a prototype to make a decision about the possibility of implementing this project. Then I have chosen architecture based on functional and nonfunctional requirements. It was clear architecture for service (the system has a lot of infrastructure dependencies: many links to other external microservices and of course databases can be vary). I have written the code in other services (Basket, Order service, Collect Order service, Order State Flow service , BackOffice service and so on) to start collaborating old services with new ones via my service. I have covered almost all use cases by written end-to-end tests to be sure any time my service is working well. As a result, users can start using a new website that can collaborate with new Basket service and other services of the new ecosystem and at the same time pass the data to the old system via my integration service to be sure the data in the old system is the same as in the new one. I have done a lot of UML diagrams. I collaborated as a mentor to junior developers who  made the tasks according to the project needs.        

The project stack: MS SQL Server, EF Core, ASP.NET Core, RabbitMQ, Swagger, XML, JSON, xUnit(unit, e2e tests), UML(Enterprise Architect), CQRS(Mediatr)