Use as a standalone proxy server

(from project README)

// Listen on a specific host via the HOST environment variable
var host = process.env.HOST || '0.0.0.0';
// Listen on a specific port via the PORT environment variable
var port = process.env.PORT || 8080;

var cors_proxy = require('cors-anywhere');
cors_proxy.createServer({
    originWhitelist: [], // Allow all origins
    requireHeader: ['origin', 'x-requested-with'],
    removeHeaders: ['cookie', 'cookie2']
}).listen(port, host, function() {
    console.log('Running CORS Anywhere on ' + host + ':' + port);
});

Use as a library in an existing (node+express) server

(with thanks to @Jelledb https://github.com/Rob--W/cors-anywhere/issues/81#issuecomment-348436866 )

let proxy = corsAnywhere.createServer({
    originWhitelist: [], // Allow all origins
    requireHeaders: [], // Do not require any headers.
    removeHeaders: [] // Do not remove any headers.
});

/* Attach our cors proxy to the existing API on the /proxy endpoint. */
api.get('/proxy/:proxyUrl*', (req, res) => {
    req.url = req.url.replace('/proxy/', '/'); // Strip '/proxy' from the front of the URL, else the proxy won't work.
    proxy.emit('request', req, res);
});