What it is: harada-grid.com — a free maker for the mandala chart (1 goal → 8 themes → 64 actions). Stack: one `index.html`. Vanilla JS, no framework, no build step, no server, no database. Charts live in localStorage; share links pack the whole chart into the URL hash. PNG export is drawn by hand on a canvas. Monetization without a backend: Pro ($9 once) = unlimited charts + 8 filled-in templates. Gumroad generates a license key per sale, and their license-verify API allows browser requests (CORS), so the page checks the key with one `fetch` and stores the unlock locally. No accounts, no Stripe webhooks, nothing to host. Trade-offs I accepted: no cross-device sync (same key works on each device, plus a backup export/import), and the unlock is bypassable with devtools — fine at $9. First paid tool I've shipped after building ~8 that I never monetized. Happy to answer anything about the Gumroad trick, and I'd love blunt feedback on the free → Pro upgrade prompt.   submitted by   /u/oldSchoolwalrus [link]   [comments]