Product · Commerce — Design collaboration with DSL4 Digital, 2026
Papertill
Sell a file. Keep the money. A complete digital-product checkout in one Cloudflare Worker — sold as a $29 kit whose own storefront is the live demo.
Sell a file. Keep the money. A complete digital-product checkout in one Cloudflare Worker — sold as a $29 kit whose own storefront is the live demo.
A whole checkout, in one file you can read.
Selling one digital file should not require a platform, a plugin stack and a monthly fee. Papertill is a complete checkout — payment, delivery, license keys, receipts — in a single dependency-free Cloudflare Worker. It costs $29, and it sells itself: the storefront you buy it from is the product, running live, with a public sales ledger at /colophon.
DSL4 Digital engineered the checkout, delivery and signing systems. Viva Grafix designed the product story and checkout experience around that inspectable architecture, so buyers can understand what happens from payment to download.
The strongest claim a checkout kit can make is to run its own till in public.
Stripe Checkout in, signature-verified webhook, then an HMAC-signed expiring download link out — the entire commerce loop in one Worker plus KV.
Keys are stateless and deterministic — re-derivable on demand, so there is nothing to store, migrate or leak.
LSSI-CE and EU Consumer Rights Directive compliance are built into the kit, not left as an exercise for the buyer.
DSL4 Digital keeps the commerce surface small and fully verified; we made that architecture readable in the product and storefront.
A full buy-to-download verification harness runs against a mock Stripe server — the purchase path is tested as a behaviour, not as a set of units.
Stripe webhooks are signature-verified and download links are HMAC-signed with expiry — the two places a file-shop actually gets robbed.
One Worker, zero dependencies. The whole product fits in a codebase a buyer can audit over coffee.
Papertill is DSL4 Digital’s commerce engineering reduced to its honest minimum, with Viva Grafix giving it a clear product story: a till, a file, and a receipt — running live as its own proof.