Your AI built the app.Now give it real customers.
Gemmein is the customer backend for AI-built web apps: sign-in, private customer data, subscriptions, and a console for supporting the people using it.
Paste it to Claude CodeCodexCursorBoltLovable — or the stack you already have
What you're building
It doesn't matter what it is. It matters that someone signs in.
An AI tool that sells credits. Software you licence. A members' archive. A client portal. Something nobody has built yet. Gemmein doesn't know the difference between them, and doesn't need to.
It knows who is signed in, what belongs to them, and who has paid. That is the same problem underneath every one of them.
How it works
Everything anyone does in your app comes through here first.
One command puts Gemmein under whatever your AI builds. From then on every request is checked before it reaches anything: who it is, whether your rule allows it, what to hand back, whether they have paid — and what happened is written down.
You never build a line of it, and it is the same on the free plan as on the paid one.
The back office
Refund me. I can't sign in. Delete my account.
Every app with customers in it gets those emails, and an app your AI built has nowhere to answer them from. Gemmein does: every person who has signed in, what they've paid, what they did, and the controls to fix it.
The refund itself happens on your own Stripe, because that is where your money already is. You are not building an admin panel at eleven at night either way.
Pricing
What you'd otherwise have to build, secure and keep running.
Sign-in with no password database to leak. Rules held on the server, not in the browser. Every customer's data walled off from the next. Payments on your own Stripe, and no server of yours to keep alive.
All of it is on from your first command and identical on the free plan. You pay the day someone who isn't you signs in.
- Buildfreeeveryone starts here
- Live$50–$150/moone plan, set by your people — 1k → $50 · 2.5k → $75 · 5k → $100 · 7.5k → $125 · 10k → $150
- Beyondtalk to uspast 10,000 people, scale is a relationship
Questions
Asked before you have to ask.
- What is Gemmein?Sign-in, rules, data, payments and the record.
- Does Gemmein hold my money?Never. Stripe pays you, on your own account.
- How is this different from Supabase or Firebase?Fewer choices. The rules are the only rules.
- What can't it do?Web apps only — no teams, realtime or payouts yet.
- When my app is ready for real users?You move it to Live. Building stays free.
The longer answers are on the detail page.
Go build something.
You already have the idea. Gemmein is what it stands on when real people show up.
No account. No card. No time limit.