Your MCP server is live, an agent is calling its tools, and you want the tool calls to make money. The metering is the easy part - you already control the server. The slow part is the bit nobody warns indie authors about: to actually receive the money you need a merchant account, and getting one usually means a company and a review queue. paas.build gives you a real merchant account the same day, no company, and you stay the merchant of your own tool. Here's the whole path.
You already have the hook: your server sees every tool call, so metering is a counter and a check. Whichever you pick, the thing standing between you and revenue is not code - it's the account that receives the money.
go_live (or you use the console on the homepage), keys arrive by email, and you charge with a hosted checkout or a subscription. One flat rate: 3.9%, no fixed per-transaction fee - which is the whole game for pay-per-call pricing.
| On a $2 tool call | Fee taken | Effective rate |
|---|---|---|
| paas.build (3.9% flat, no fixed fee) | $0.08 | 3.9% |
| Card processor (2.9% + $0.30) | $0.39 | 19.5% |
| Merchant of Record (5% + $0.50) | $0.60 | 30% |
A 30-cent fixed fee is invisible on a $200 sale and fatal on a $2 one. No fixed fee is why per-call MCP pricing actually works here. See the full pricing.
Decide what to charge for (per tool call, credits, or a subscription), then open a merchant account that can receive the money. On paas.build you get a real merchant account the same day via progressive KYB - no registered company required - and you stay the merchant of your own tool. Meter the calls in your server, charge with a hosted checkout or subscription, 3.9% flat.
No. Individuals and sole traders can go live via progressive KYB with a capped live account (~£1,500) while verification completes in the background. That is usually the slow, blocking step for indie MCP authors, and it is the part paas.build removes. UK, EU and US builders.
x402 and crypto rails settle in stablecoins and assume the payer holds a wallet - great for machine-to-machine, poor for a human who wants to pay with a card. paas.build settles real card and bank payments in your currency to your bank account on FCA rails, so your human users can just pay. You can run both if you want.
On paas.build a $2 charge costs about 8 cents (3.9% flat, no fixed per-transaction fee). A processor charging 2.9% + $0.30 would take $0.39 on the same $2 - an effective 19.5%. Fixed per-transaction fees are what make tiny pay-per-call pricing unviable elsewhere.