Build a French HR assistant SaaS with Claude Code
I built Lumi, an HR assistant in French, with Claude Code in about two hours. It was an experiment: could Claude Code build a working product from a plain brief while being left completely alone? Employees ask questions, and Lumi answers using their company’s own HR documents. Each company has its own space, and HR can see which questions the documents couldn’t answer. Step-by-step: 1. I set up one window with Claude Code on one side and the files appearing on the other. I didn’t write code, but I could always see what was being built. 2. I described the product in plain language. I dictated my brief out loud, typos included: who pays, who uses it, the problem, a demo client, keeping clients separate, the admin view, the language, and the price. 3. I let Claude Code build the product and make every call. Thirty-four minutes later, the first version had 47 files and 3,949 lines. It even invented a fictional client company with a full HR handbook so I could demo it immediately. 4. I put the product online. Claude Code wrote a setup guide for Supabase and Vercel. I followed it one step at a time and sent a screenshot whenever something broke. 5. I improved it with feedback. I told Claude Code that the design looked like it had been created by a junior designer. Eighteen minutes later, it came back with a name, a design system, pricing plans, and everything in French. 6. I checked security, although I had skipped this during the build. When I asked for a full security review eleven weeks later, it took less than six minutes and found three serious problems, including a database function that allowed anyone to read a company’s documents. Claude Code fixed all three. Run `/security-review` before sharing the link and before each new change. The full write-up, including the unedited prompts: https://www.theaithinker.com/p/how-to-build-a-saas-product-with