Building internal tools with AI: what it took to reach production
Our internal tools, built with AI coding tools, reached first real use in days or weeks. Replacing the spreadsheets behind them took longer by design: a parallel run with an exit rule of three weeks with no differences, and reconciliation that showed the old tools were often the ones that were wrong. Inside the tools, AI reads unstructured input while hours and money stay in deterministic code.
Alex Marciuc - 23 Oct 2026


