I Built a Mini Derivatives Exchange in Python. Here's How I Used Cursor Without Letting It Run the Show.

This year I wanted to level up in AI assisted coding as a senior engineer. Also I have interests on Trading. So I built a paper derivatives exchange: order book, limit and market orders, matching engine, positions. Python, FastAPI, PostgreSQL. I used Cursor the whole time, but not the way you might think. I didn't type "build me an exchange" and hit enter. I wrote the architecture first. Then I drove Cursor one module at a time. That made all the difference. If you're thinking of building something like this with an AI pair programmer, here's what actually worked for me. Write the plan before you write (or generate) any code The first thing I did was open a doc, not the IDE. I wrote a single architecture and projects file. In it I spelled out: How repos are split (frontend and backend always separate, one deployable per backend). Which repo does what (exchange API, demo UI, where gamification would plug in later). Tech choices: FastAPI, PostgreSQL, Binance public API for prices. Why no