You (or your AI) made something real: it runs, it looks right, people could use it. The gap between that and "strangers pay for this" is always the same list — real accounts, private data that stays private, payments someone actually operates, and a place to run the business from. This page is the path across that gap.
The pain isn't building the app. It's taking it to customers. That's the part Gemmein sells.
Paste it to the AI you already build with — Claude Code, Codex, Cursor, Bolt — it reads the guide and answers for your app.
Paste one prompt to whichever AI you build with. It reads the builder guide, maps your app against what Gemmein supports — sign-in, records under safety rules, subscriptions and one-off sales, file delivery — and tells you fits, fits-except, or doesn't before anything installs. If it doesn't fit, you've lost five minutes, not a migration.
npx -y gemmein dev boots a complete local backend with zero setup — sign-in codes print in the terminal, payments are simulated through the exact machinery production uses, and the safety rules are enforced the same way live. No account exists yet. Nothing leaves your machine.
npx gemmein sync is the first moment a human signs up (free). Paste your Stripe Payment Link, set your prices, and npx gemmein go-live flips it. From that day the console is your back office: customers, subscriptions, refunds through Stripe, and an audit record of everything.
Questions
Building is free indefinitely — no card, no time limit. Live is one banded plan: $50/mo up to 1,000 verified monthly people, stepping to $150/mo at 10,000, set by the previous month's real people. Beyond that, you talk to Gemmein. Your customers' money never touches any of it — that lands in your own Stripe.
No. Gemmein never hosts your app — it's the backend underneath. Your frontend stays on Vercel, Cloudflare, or wherever it lives; it talks to Gemmein through a small SDK your AI wires in.
You do — deliberately. With Gemmein, every payment lands in your Stripe account and the customer is legally your customer. Merchant-of-Record platforms (Paddle, Lemon Squeezy) flip that trade: they become the seller of record, their name is on the card statement, and your customer is contractually theirs — in exchange they carry the tax filing. Both are legitimate. Selling digital products to EU consumers can create VAT duties from the first sale, and at heavy international volume a Merchant of Record genuinely earns its cut. For most independent founders under the UK's £90,000 VAT threshold, with Stripe Tax able to calculate what's owed, you're deciding whether to hand over the customer relationship to avoid paperwork you may not have yet. Gemmein never holds, moves, or processes money either way — that's Stripe's job, in your account.
Web apps only — no native mobile SDKs today. No team or workspace visibility scopes, no per-user record permissions, no carts or physical goods, no multi-seller payouts, no hosted functions or cron (your server-side code runs on your own host with a secret key). If something isn't in the builder guide, it isn't built — the guide says so out loud rather than letting an AI invent a workaround.
No account. No card. No time limit.