Overview
Veto Checkout is the seller-side SDK of the Veto ecosystem — let any AI agent discover your products and check out autonomously, while you verify the buyer and run your policy before taking a cent.
Veto Checkout is the merchant-side SDK of the Veto ecosystem. You mount it under
your own domain so that any AI agent — ChatGPT, Gemini, LangChain, or a curl
script — can discover your products and check out autonomously, while you
verify the buyer's authorization and run an acceptance policy before you take a cent.
Veto (the buyer-side product) governs the agent — "may my agent spend $X here?" — and issues a signed mandate. Veto Checkout is the mirror image: it verifies that mandate, runs your policy, settles on a pluggable rail, and issues a merchant-side signed receipt that links back to the buyer's mandate. Two signed artifacts pointing at each other are your dispute evidence.
Veto governs · the rail executes.
Mandate verification and policy run locally — zero latency, and they work even if the hosted services are down. The rail only ever executes a spend the gate already approved.
What you get
Open to all agents
A presented mandate is optional and polymorphic (veto | ap2 | acp | none). A
Veto-governed agent is simply the highest-trust input — never a requirement.
Non-custodial
Veto never holds funds. You bring your own receiving address; the only key Veto holds signs receipts, not value.
Rail-agnostic, x402 first
The Rail is a pluggable interface. v1 ships x402 (HTTP-402 + stablecoin) and mock
(offline tests); card is a typed stub.
The acceptance gate
Verify the mandate, check replay, look up reputation, run policy — all before any money is captured. The order is the chargeback defense.
Start here
Quickstart
A fully self-describing agentic checkout in 30 seconds, then settle a mock order.
Agentic Checkout Protocol
Every endpoint, status code, and reason code — the self-describing wire protocol agents talk to.
SDK · CLI · MCP
The @veto-protocol/checkout SDK, the veto CLI, and the MCP server.
Reason codes
The stable, machine-actionable rejection vocabulary an agent keys off.