Our product is a logistics SaaS for regional freight carriers: quoting, dispatch, tracking, invoicing and a customer portal. It started as one Django application and, eight years later, was 410,000 lines of Python, one PostgreSQL database with 640 tables, and a test suite that took 48 minutes. Deploys were weekly because every deploy risked everything. When we started planning a migration, the first proposal had thirty services on a whiteboard, one per noun in the domain. We did not do that. Thi...