DIGITAL PRODUCT · $79 · INSTANT DOWNLOAD
A small, readable Cloudflare Worker that charges AI agents per tool call on your MCP server, over the Machine Payments Protocol, on your own Stripe account. It is the pattern SET runs on its own paid MCP endpoint, without SET's accounts or secrets.
A stateless Streamable HTTP endpoint for JSON-RPC: initialize, tools/list and tools/call, with arguments validated before any payment is asked for. One example paid tool and a free tool that lists prices; put your own tool where the code says.
An unpaid tools/call answers JSON-RPC error -32042 with a Machine Payments Protocol challenge (mppx's MCP transport). The agent pays by card or Link through a Stripe Shared Payment Token, retries with the credential, and gets the result with a receipt. Payments settle to your own Stripe account.
A D1 table keyed by idempotency key, so a retried call returns the paid result without a second charge, plus an optional prepaid-key path whose debit is one atomic statement. Tests run on node:sqlite against the real migration.
You pay on this page through Stripe. After payment you are taken to a download page for a zip containing TypeScript source, a D1 migration, a node:test suite and a README with setup steps and the 402 flow. The download link works for 30 days from purchase or up to 10 downloads, whichever comes first. Requires a Cloudflare account and a Stripe account; Stripe decides whether your account can accept machine payments. USDC and x402 are not included.
For business purchases only. The kit is licensed for your business's internal use; resale and redistribution are not allowed. You may request a refund within 3 days of purchase if you have not downloaded the kit, and a refund ends your download access and license. By buying, you agree to the Terms of Service (sections 3.5 and 4, which apply to this kit as they do to the Starter Kit) and the Privacy Policy.
Selling a REST API instead of MCP tools? The Embedded Checkout Starter Kit covers checkout pages, and SET installs paid HTTP 402 endpoints on the Custom Build page.
BUILT ON STRIPE, PRIVY AND BRIDGE
SET Private Wallets run on Privy and Bridge, and SET's payment builds run on Stripe. Each provider's own documentation is the final word on how its part works. Links checked on .
Payments, Connect and the crypto onramp. Stripe completed its purchase of Bridge in February 2025 and announced it was acquiring Privy in June 2025.
The wallet: email sign-in and self-custodial wallets only you can spend from.
Your US account number, the conversion to stablecoins, and cash-out to your bank.
Simple Easy Transactions is a separate company from Stripe, Privy and Bridge. It uses their services under its own accounts; they do not endorse SET.