HTTP 402 payments for AI agents & tokenized APIs

// Gate an Express route with HTTP 402
import { setupChannel } from "@channel-sdk/nodejs";

const { monetize } = setupChannel(app, endpoints, { merchantWallet });

app.get("/api/v1/greeting",
  monetize(5),
  (req, res) => res.json({
    message: "Hello",
    fee: req.payment!.fee
  })
);

// AI agent or backend — self-custodial wallet
import { ChannelClient, withChannel } from "@channel-sdk/nodejs";

const client = new ChannelClient({
  baseUrl: process.env.DEMO_SAAS_URL,
  mnemonic: process.env.CHANNEL_MNEMONIC,
  clientSource: "ChannelCash",
});
const pay = withChannel(client);

const { data, fee } = await pay(
  "/api/v1/greeting",
  {},
  { maxAmount: "0.01" }
);
console.log(data, fee);

// Browser — extension signs, wallet holds keys
import {
  ChannelBrowserClient,
  ExtensionWalletProvider,
  withChannelBrowser,
} from "@channel-sdk/browser";

const wallet = new ExtensionWalletProvider();
const client = new ChannelBrowserClient({
  baseUrl: import.meta.env.VITE_DEMO_SAAS_URL,
  wallet,
});
const pay = withChannelBrowser(client);

await wallet.connect({ origin: window.location.origin });
const { data, fee } = await pay(
  "/api/v1/greeting",
  {},
  { maxAmount: "0.01" }
);