Merchant Integration

This is the landing page for the merchant integration track. It explains SohoPay’s closed-loop merchant model, where trust is enforced, and how fees work — then points you at the four guides that take you from signup to production. Budget roughly 3–5 days for a full integration.

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The closed-loop merchant model

SohoPay is a closed loop: agents can only pay merchants that have registered with SohoPay, and merchants only receive payments from agents they have explicitly approved. There is no open “pay any address” mode. The loop has three parties:

• Merchant — you. You register, complete KYB, and maintain an allowlist of agents permitted to pay you.
• Agent — an AI agent with a SohoPay-managed wallet and a credit line, created by an operator.
• Operator — the business running the agent. The operator funds the credit line and is liable for the agent’s transactions, so you are never chasing an autonomous bot for payment.

Why closed-loop? It lets every payment be pre-authorized against known counterparties. The Policy Service refuses to co-sign any settlement to a merchant that hasn’t allowlisted the paying agent, so fraud prevention happens before funds move — not after.

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Payment flow at a glance

Settlement is on-chain USDC on Base with roughly one-second finality. There is no T+1 batch cycle — the moment a payment settles, the USDC is in your payout wallet.

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Trust boundaries

The critical property: your allowlist is enforced on-chain, not just in an API layer. Every settlement requires a 2-of-3 MPC signature. One key belongs to the agent; the other is held by the Policy Service, which checks four things before co-signing:

1. The paying agent is on your allowlist
2. The agent has sufficient credit
3. The agent is within its per-agent rate limits
4. The agent’s wallet passes AML screening

If any check fails, the Policy Service withholds its signature and the settlement is cryptographically impossible — the API returns an error such as 403 AGENT_NOT_ALLOWLISTED instead. The system is fail-closed: if the Policy Service is down, no settlements happen at all.

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Fee structure

SohoPay charges a 5% fee per transaction, paid by the operator — never by you. If an agent pays a 100 USDC order, you receive 100 USDC and the operator’s credit line is drawn for 105 USDC. There are no merchant-side deductions, no reserve holds, and no monthly minimums. See Fees for the full breakdown.

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Integration roadmap

The merchant track is four guides. Work through them in order:

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Next steps