Papers The Written Surface of the Network
The Written Surface of the Network
A map of where the network writes things down: specifications, references, machine specs, guides and history, each with its canonical home.
One door, many rooms
The network documentation lives where its surfaces live. docs.u.cash is the map; papers.u.cash (this site) holds the formal canon as authored papers; library.u.cash is the catalog of guides, references and archives. Nothing here is a copy of record: every paper links its canonical upstream.
The canonical homes
- Merchant documentation: pay.u.cash/docs - checkouts, payment links, payouts, webhooks, invoices, test mode.
- Agents API reference: agents.u.cash/reference - the REST surface for priced resources, wallets, challenges and settlements.
- SDKs: sdk.u.cash - JavaScript and Python packages plus the MCP server, install to first payment.
- Protocol: 402.onl - the vendor-neutral 402 spec and the UCP discovery profile.
- Machine spec: agents.u.cash/openapi.json - structured spec for tooling and SDK generation.
- Plain text: agents.u.cash/llms.txt - the entire agents surface in one file, for LLMs.
- Guides: pay.u.cash/learn - long-form guides across payments, shops, invoicing and operations.
- Fleet health: status.u.cash - uptime history and the public statistics dashboard.
- The catalog: apps.u.cash - every app on the network with its lifecycle stage.
Staying current
Two surfaces move daily: status.u.cash for fleet health, and the apps.u.cash changelog for what shipped, per app, per day. When a number in any paper drifts from its upstream, the upstream wins; papers carry the updated date above to make drift visible.
This paper condenses a canonical source. When details drift, the upstream wins: docs.u.cash.