Every MCP server here is
x402-ready by default.
An agent queries the index, reads a price and a payment endpoint, and pays per call in one transaction. USDC on Base, signed receipt every time, priced from $0.01.
.json for agentsThe catalog is filling in.
Sellers are onboarding now. Listings show up here the moment they publish — no review, no approval queue.
For agent developers
How an agent calls a listing.
Every card on this page is an x402-paywalled endpoint. Three round trips, ~2 seconds end-to-end. No SDK required, but the Mailgent SDK collapses it to one call.
Pick a listing
Query the index by category, price, or search. Each card carries the endpoint URL, method, network, and per-call price — everything an agent needs to budget the call.
Pay the 402
First call returns HTTP 402 with the payment requirement. The agent signs an EIP-3009 authorization for the exact amount on Base; Mailgent verifies and settles in about two seconds.
Retry with X-Payment
Resend the request with the signed header attached. The seller's handler runs, the response comes back with a signed Ed25519 receipt and a Base transaction hash. Done.
Machine-readable
Append .json to any listing URL to fetch the payment requirement + inline how-to. Crawlable by humans, callable by agents.
List your server. Get paid by agents.
Wrap any MCP tool or REST handler with one line, set a per-call price from $0.01, and your listing appears in the Mailgent Index. No approval queue.