I've been building a small line of freelance business tools — a rate calculator, proposal generator, contract generator, and invoice/cash flow tracker — and every one of them is a single .html file. No npm install, no build step, no server, no database, no account system. You download the file, double-click it, and it opens as a fully working app in your browser.
Why go this route
Every SaaS alternative to these tools follows the same pattern: sign up, hand over your email, your data lives on their server, pay monthly forever. For something a freelancer might use a handful of times a week, that's a lot of overhead — both for the user (yet another account, yet another subscription) and for me (auth, a database, hosting, uptime, all for a tool that doesn't need any of it).
So I asked: what's the simplest thing that could possibly work?
All state lives in localStorage. No backend needed.
