Express.js

npm install express http-proxy-middleware

const express = require("express");
const { createProxyMiddleware } = require("http-proxy-middleware");

const app = express();

// Proxy tracking script
app.get(
  "/api/track.js",
  createProxyMiddleware({
    target: "https://your-postmetric-domain.com",
    changeOrigin: true,
    pathRewrite: {
      "^/api/track.js": "/api/track.js",
    },
    onProxyRes: function (proxyRes, req, res) {
      proxyRes.headers["content-type"] = "application/javascript";
    },
  })
);

// Proxy tracking endpoint
app.all(
  "/api/track",
  createProxyMiddleware({
    target: "https://your-postmetric-domain.com",
    changeOrigin: true,
    pathRewrite: {
      "^/api/track": "/api/track",
    },
  })
);

app.listen(3000);

<script src="https://your-domain.com/api/track.js?site=YOUR_TRACKING_CODE"></script>