Launch an API agents pay for

Connex is the agentic x402 launchpad for APIs. You put a price on an endpoint with x402, launch it here, and AI agents can find it and pay for each call in stablecoins. Agents need no API keys, accounts or invoices.

Connex currently lists 4.1K projects and 119.1K paid endpoints, which handled 904.9K paid calls in the last 30 days.

x402 uses the HTTP status code 402 Payment Required. Payment happens inside a normal HTTP request:

1. The agent calls your endpoint.
2. Your server answers 402 with a PAYMENT-REQUIRED header: the price, the network and your payTo wallet.
3. The agent signs a stablecoin payment and retries with a PAYMENT-SIGNATURE header.
4. A facilitator verifies and settles the payment on-chain, and your server returns the data. The money lands in your wallet.

Prices can be fractions of a cent, so per-call pricing works for data, inference and tools that would never justify a subscription.

Or run x402 on your own server:

npm install @x402/express @x402/core @x402/evm

import express from "express";
import { paymentMiddleware, x402ResourceServer } from "@x402/express";
import { ExactEvmScheme } from "@x402/evm/exact/server";
import { HTTPFacilitatorClient } from "@x402/core/server";

const app = express();
const payTo = "0xYourWalletAddress"; // where payments land

// Testnet facilitator (Base Sepolia). Switch to a mainnet facilitator to go live.
const facilitator = new HTTPFacilitatorClient({ url: "https://x402.org/facilitator" });

app.use(
  paymentMiddleware(
    {
      "GET /weather": {
        accepts: [{ scheme: "exact", price: "$0.001", network: "eip155:84532", payTo }],
        description: "Current weather for a city",
        mimeType: "application/json",
      },
    },
    new x402ResourceServer(facilitator).register("eip155:84532", new ExactEvmScheme()),
  ),
);

app.get("/weather", (req, res) => {
  res.json({ city: "Lisbon", weather: "sunny", tempC: 24 });
});

app.listen(4021);

curl -i http://localhost:4021/weather
# HTTP/1.1 402 Payment Required
# PAYMENT-REQUIRED: <price, network and payTo, base64-encoded>

Read-only JSON, free while in beta. No key, open CORS, and responses are cached for 5 minutes. Full parameters and examples are on the API reference page.

GET /api/v1/pro/endpoints searches individual endpoints across the whole catalog and returns what an agent needs to call and pay them: URL, method, price, network, asset, payTo, scheme, facilitator and 30-day usage. Filter by q, network and maxPrice (USD), sort by popular or price, up to 200 results per page. Testnet endpoints are left out.

It is paid per call with x402, so there is no key or account: the agent pays and gets the data.

Coming soon. The Pro API will accept USDG and $CONNEX on Robinhood Chain. Until it is switched on, it answers 503.

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { ExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const signer = privateKeyToAccount(process.env.AGENT_PRIVATE_KEY as `0x${string}`);
const client = new x402Client();
client.register("eip155:*", new ExactEvmScheme(signer));
const fetchWithPayment = wrapFetchWithPayment(fetch, client);

// Endpoints under $0.01 matching "weather", cheapest first
const res = await fetchWithPayment(
  "https://connex.fun/api/v1/pro/endpoints?q=weather&maxPrice=0.01&sort=price",
);
const { data } = await res.json(); // url, method, priceUsd, network, payTo, ...

Paying with USDG

USDG (Global Dollar) on Robinhood Chain supports EIP-3009, so each payment is a single signature: no approval step and no gas for the agent. Hold USDG on Robinhood Chain and the x402 client above handles the rest.

Paying with $CONNEX

$CONNEX payments run on Robinhood Chain through Permit2. Before the first payment, the paying wallet approves the Permit2 contract (0x000000000022D473030F116dDEE9F6B43aC78BA3) to spend its $CONNEX, once, which needs a little ETH on Robinhood Chain for gas. After that, each call is a signature and the agent pays no gas.

• Paid services come from the Coinbase CDP and PayAI Bazaar discovery catalogs. Endpoints are grouped into one project per host, with price, network, facilitator and 30-day usage for each.
• Ecosystem projects such as facilitators, SDKs, extensions and explorers are checked by hand.
• Testnet-only services are hidden. The catalog is re-imported periodically, so new endpoints can take a while to appear.
• Usage numbers are paid calls reported by facilitators over the last 30 days.

The official $CONNEX contract address is:

$CONNEX can be used to pay for the Pro API once it is switched on.

The address is also in the bar at the top of every page. Always check it on connex.fun before you buy: copies posted elsewhere can be fake. Nothing on this site is financial advice.

1. Phase 1

   Live
   • Hosted x402 gateways for any APILaunch from the dashboard, get paid per call
   • Pay per call in USDG or $CONNEXOn Robinhood Chain, settled by Connex's own facilitator
   • Owner dashboard and on-chain receiptsPaid calls, earnings and tx links
   • AI agents paying liveCodex demo and the agent payment example
   • Agent PlaygroundAsk a question, watch an agent pay in $CONNEX
   • Official Connex APIs$CONNEX price, New Launches and Risk Checker

2. Phase 2

   Building now
   • Connex agent bot for Telegram✓ CompleteLive at t.me/connexagentbot: ask in a DM or a group, with free daily answers
   • More high-quality official APIsIn progressIdeas: wallet portfolio, transaction explainer, page to clean text
   • Connex MCP serverUp nextClaude, Codex and other agents find and pay APIs natively
   • Agent SDK and CLIUp nextWith spend limits built in
   • Webhooks and payout analyticsUp nextFor API owners

3. Later

   Later
   • Base and Solana supportLaunch and pay for APIs on more chains, beyond Robinhood Chain
   • APIs from other platformsThe agent uses and pays x402 APIs from platforms like PayAI and Coinbase
   • Verified API listings and reputation

Plans can change as we learn what agents and builders need. Follow along on X and Telegram.

Does Connex take a cut of payments?

No. Agents pay your payTo wallet directly through the facilitator; Connex never holds or routes payments for listed APIs. The only payments Connex receives are for its own Pro API.

Does Connex host my API?

No. Your API runs wherever it runs today. Connex lists it so agents can find it, with its price, network and usage.

How much does it cost to launch?

Nothing. Listing is free, whether your API is picked up from a facilitator catalog or launched through the form.

Is the discovery API free?

Yes, with no key. The Pro API adds paid, endpoint-level search, paid per call with x402.

My listing is wrong or out of date. How do I fix it?

Open your project page and use Suggest an edit, or send the details through the launch form. Edits are reviewed by hand.

Which networks are supported?

Whatever your facilitator supports. Most listed endpoints settle on Base, followed by Solana, Polygon, Arbitrum and others. Testnet-only services are hidden.