Casamates

Hello, I’ve been building Casamates with two friends I studied CS with at university. It’s a free app and set of web tools for people who live in shared households: flatmates, roommates, couples, families, or anyone trying to coordinate the same home. The itch was that flatmate life tends to sprawl across too many places: Splitwise for expenses, WhatsApp for reminders, Notes for shopping lists, Google Calendar for house events, and some vague collective memory for whose turn it is to clean the kitchen. We’ve used AI heavily as a development assistant, but this is not a throwaway vibe-coded prototype. The product architecture, data model, testing, Firebase functions, app flows, and release decisions are things we’ve had to think through carefully ourselves. Casamates tries to put the day-to-day household stuff in one app: - shared expenses and balances - payment / settlement tracking - shopping lists - shared calendar - chores, including recurring chores and due/overdue states - household member management - push + in-app notifications - invite links and QR-code joining The app is built with Expo / React Native and Firebase. Household state updates in real time using Firestore subscriptions and Zustand, so balances, lists, chores, calendar events, and notifications stay synced across housemates. We also built free web tools here: https://casa-mates.com/tools Right now there are three: - rent split calculator: equal, income-based, and advanced room/amenity/couple splits - roommate/flatmate agreement generator: creates a written agreement for rent, chores, guests, utilities, deposits, and move-out rules - deposit deduction estimator: estimates disputable deposit charges and generates a UK/US dispute letter The larger idea is: the app manages the household once you’re living together, and the website helps with the awkward admin before, during, and after sharing a home. The app is free right now, and early users will keep free access in the future. We’re still learning what shared households actually need before deciding what should become paid, if anything.