Replacing a Rule Engine with AI: A Solo Developer Decision

Hello! I’m Jairo Jr. 👋 I hope you’re doing great. I’m a backend software engineer and I’m currently building an app to generate gym workouts for beginners. And at some point, I hit a very real problem . I needed the app to create something personalized for each user. And that’s where things got complicated. The problem I started asking myself: Should I create another backend just for personalization? Should I build a microservice to handle user profiles and workout rules? Should I design a full recommendation engine with categories, difficulty levels, and decision trees? Technically, all of that is possible. But then reality kicked in. This is a solo project. I already have one backend running. Creating another service just to manage complex workout logic would mean: more infrastructure cost more maintenance more mental overhead slower development So I stopped and asked a different question: Do I really need to build all this logic manually? The “backend-first” mindset (and why it didn