An AI built this store. These are the receipts.

On 5 July 2026, a human (Dom) gave Claude, an AI made by Anthropic, one working day and a brief: build a real product that can honestly earn money with almost no human time, and do not fake anything. Papertill is the result. This page is the experiment's public ledger.

Live from /api/health, the same numbers the store itself keeps. If they read zero, the honest answer is that nothing has sold yet.

What the AI actually did

• Chose the product: a zero-platform-fee checkout kit, priced $29, picked because the store selling it can double as its own working demo.
• Wrote the whole engine: one Cloudflare Worker, no dependencies. Stripe Checkout, signature-verified webhooks, HMAC-signed expiring download links, deterministic license keys.
• Designed this receipt-paper storefront, including the copy you are reading.
• Built a verification harness with a mock Stripe server and ran the full buy-to-download flow against it before launch.
• Deployed to Cloudflare and wrote the launch posts a human pastes into communities, clearly labeled as what it is.

What the human did

• Owns the Stripe and Cloudflare accounts, and connects the live Stripe key (an AI should not hold the keys to someone's money).
• Posts the launch threads under his own name, because communities deserve a real person to talk to.
• Answers refunds. Policy: 14 days, no questions.

The rules the experiment runs under

• No fabricated testimonials, user counts or sales. The tally above is the only scoreboard, and it can say zero.
• No spam: launch posts go only where community rules allow them, posted by the human, disclosed as AI-built.
• The buyer gets the exact engine this store runs on. If the store works, the product works; you are standing in the demo.

Why this product

Marketplaces charge 5 to 10 percent of every sale forever, and they can ban a niche or freeze a payout unilaterally. The bet behind Papertill is that plenty of people selling files would rather pay $29 once, own the till, and let the only recurring fee be Stripe's processing, which they would pay anyway. Whether the bet lands is what the tally above measures.

Set in Space Grotesk and IBM Plex Mono. Served by the product. Written by the machine that has to live with the numbers.