One workspace to rule them all — Part 0: Where do I put my files?

I set out to build a simple pizza app. But I’m a perfectionist, so it became a monorepo.

What started as a scraper and a Streamlit dashboard turned into a Streamlit frontend, a FastAPI backend, a batch worker, three service libraries, a shared package, Postgres and S3-compatible storage, all in one repo, glaring at me like a family portrait nobody wanted to pose for. Which raised the question that has started more Slack arguments than tabs-vs-spaces: how do you actually organise all of this?

Part 0 is the prologue. It speed-runs how we got here: the monolith, the great repo scattering into microservices, the monorepo swinging back, and then gets specific about why Python in particular made monorepos miserable for so long. Spoiler: it was never the folders. It was the dependency wiring between them, held together with pip install -e ../, tape, hope, and a PYTHONPATH you were too afraid to look at directly.

No code in this one. Just the argument the rest of the series is built on: folder structure isn’t about tidiness, it’s about declaring dependencies you can actually enforce.