Implement Node.js as proxy server. It can handle its own api and can get data from other servers.

node-proxy-server.js

/*
    This proxy handles 2 types are api.
      1. Local Api: which send data from local server ex: Routes will start with /api/*
      2. Remote Api: Which takes request from user (frontend/mobile/etc) -> sends it to remote server -> sends response to user. 
          You can use routes starts with your own filter ex: /remote/* 
*/

var express = require('express');
var httpProxy = require('http-proxy');
var bodyParser = require('body-parser');
var cors = require('cors');

var app = express();

//Root Route
app.get('/',function(req,res) {
    res.send("Server is running, Please contact admin to access api's");
});

//Setup Proxy and Proxy routes

// You can divide it into separate module
var options = {
    timeout: 15 * 60 * 1000,
    target: {
        host: "www.yourhost.com",
        port: 8080
    },
    proxyTimeout: 15 * 60 * 1000
}

var proxy = httpProxy.createProxyServer(options);
proxy.on('proxyReq', function(proxyReq, req, res, options) {
    //You can check req data
});

proxy.on('proxyRes', function (proxyRes, req, res) {
    //You can do your modifications if you want to add anything to remote server response
});

app.all('/remote/*', function(req, res, next) {
    //You can do your modifications if you want to add anything to remote server request
    //You can modify headers, req url and etc
    proxy.web(req, res, next);
});

//Add your body parser after your proxy routes, otherwise it will modify request object and it will fall into errors.
app.use(bodyParser.json()); // for parsing application/json

//Use cors after proxy routes as remote server will have its own cors, if not you can use this for both servers by adding at top
app.use(cors());

//Local routes
app.use('/api', function(req, res) {
    res.status(200).send('Working...');
});

app.listen(3000, function() {
    console.log("Server is running on port 3000");
});