DarkMint

DarkMint is a robust, production-ready wallet and payments system built to demonstrate the capabilities of autonomous multi-agent software development. The entire application was constructed by a 3-seat AI "Dark Factory" consisting of specialized agents: an Architect (for API and schema design), a Developer (for backend and frontend implementation), and a Reviewer (for testing and invariant verification). The core of DarkMint is built on FastAPI and a SQLite database utilizing WAL mode to ensure strong concurrency safety. We implemented a strict double-entry bookkeeping system where money is never created or destroyed, only transferred, ensuring perfect ledger balance at all times. Balances are computed dynamically from the ledger rather than stored mutably, eliminating a major class of race conditions. Furthermore, the system avoids floating-point math entirely by using integer cents, guarantees idempotency for network retries, and supports safe transaction refunds that preserve historical ledger data. The entire stack, including a vanilla HTML/JS frontend, is fully containerized with Docker, requiring no outbound network access at runtime.