We have a large and mature codebase, but we're always iterating with new features. These often require data entry by experts in the company (in our case, stylists, marketers, copy-editors, etc), and the first-pass at the CRUD behaviour is usually just a spreadsheet. Everyone understands them, and most editing/coordination is done in a sheet while a developer builds the models and front-end in the main site (Django), then a simple import script using the Python Sheets API sticks all the data in the database in one go. The second iteration is usually a simple management interface of some sort or user-preferences.