“I cannot incur any AI cost because AI usage cost me money... that was step one to make it bring your own keys. And the second step was to not even incur any server cost... the easiest way to do that was to just use the users' computers. And to do that I had to build a desktop app. This allows me to ship and forget about my business cost.”

Re-Architect As Electron Plus BYO Keys So $50 Of Monthly Opex Funds The Whole Business

To make a one-time-purchase model viable, Pren re-architected the web SaaS into an Electron desktop app where users supply their own API keys and the app runs on their hardware. Result: no AI bill, no servers — roughly $50/month total opex on an $80K business. The architecture is what made the LTD math work and is replicable for any AI wrapper.