Cross-post notice: this is the canonical version. Reposts on Medium, Hashnode, and Indie Hackers will link back here. A few months ago I shipped a free invoice generator. The kind of tool freelancers find at 11pm when a client wants an invoice and they don't want to register on a CRM just to send a PDF. The whole product runs under four hard constraints I refused to break: 100% online — open the U