&gt; As an example: My personal pet peeve is the startup world&#x27;s ignorance of Domain-Driven Design and CQRS (Command-Query Responsibility Segregation). If you want to make scalable backends, I really recommend you read up on CQRS, it&#x27;s practical and it fits modern ideas. Most examples are in C#, but you&#x27;ll survive.<p>Most starts never become successful enough to have to worry about scalability; in fact, if they do, it&#x27;s almost a luxury.<p>I don&#x27;t have experience with CQRS and event sourcing, but it does seem to come with its own share of problems, for example dealing with changes of the data model, which I suspect would happen often in young businesses.