Payment rails should be open.

The internet runs on open protocols — HTTP, DNS, SMTP — that anyone can implement, run, and build on without permission. Payments are the conspicuous exception. Online commerce still routes through a layered stack of intermediaries — networks, processors, gateways, issuers, acquirers — each taking a fee, adding latency, and reserving the right to refuse service. Cross-border settlement is slow and expensive. Refunds and disputes happen off-rail. Programmable money, twenty years into the API economy, is still mostly marketing.

Stablecoins changed the substrate. A dollar can move between two wallets in under a second, anywhere in the world, for fractions of a cent, without anyone's permission. But a transfer alone isn't commerce. Commerce needs the primitives card networks have always provided — authorization, capture, refund, dispute windows — around the bare movement of money. So far, the only way to get those primitives has been to plug back into the legacy stack and inherit its costs.

rail0 is the alternative: a single immutable contract that implements the full authorize → capture → refund lifecycle for stablecoin payments, with no owner, no admin, no fee, and no privileged operator. Buyer and merchant transact directly. A payment takes one off-chain signature — the buyer signs an EIP-3009 authorization, the merchant submits the transaction and pays gas. No allowance, no smart-account wallet, no bundler, nothing broadcast to set it up. It accepts any EIP-3009-capable stablecoin, runs on any EVM-compatible chain, and adds nothing between buyer and merchant beyond the rules of the contract itself — rules that are public, immutable, and the same for everyone.

The zero in rail0 is literal: zero intermediaries, zero protocol fees, zero privileged operators, zero permission required to deploy or to use. It also marks day zero — the moment payments stop being a service rented from someone else's network and become a commodity protocol the way HTTP is.

Payment rails should be open like the rest of the internet. That is the mission. If we get this right, rail0 is the last payment rail the new era needs.