MPP quickstart for pay-per-use X API requests

npm i mppx viem

mppx account create             # generates a local keychain-backed account
mppx account export             # prints the hex private key (0x...)

import { Mppx, tempo } from "mppx/client";
import { privateKeyToAccount } from "viem/accounts";

// Configure the MPP client. This patches global fetch
// to automatically handle 402 Payment Required challenges
Mppx.create({
  methods: [
    tempo({
      account: privateKeyToAccount(process.env.TEMPO_PRIVATE_KEY as `0x${string}`),
    }),
  ],
});

// Now any fetch to an MPP-enabled endpoint auto-pays
const response = await fetch("https://xquik.com/api/v1/x/tweets/1893456789012345678");
const data = await response.json();
console.log(data.tweet.text);

curl -i https://xquik.com/api/v1/x/tweets/1893456789012345678

HTTP/2 402
WWW-Authenticate: Payment id="abc...", realm="xquik.com", method="tempo", intent="charge", request="eyJhbW91bnQiOi..."

curl -i https://xquik.com/api/v1/x/tweets/1893456789012345678 \
  -H "Authorization: Payment eyJjaGFsbGVuZ2UiOnsi..."

HTTP/2 200
Payment-Receipt: eyJzdGF0dXMiOiJzdWNjZXNzIiwi...
Content-Type: application/json

{"tweet": {"id": "1893456789012345678", "text": "..."}}