I'll suggest to check request module or specifically this part of the documentation https://github.com/mikeal/request#forms
Here is an example:
var r = request.post('http://service.com/upload', function optionalCallback (err, httpResponse, body) {
if (err) {
return console.error('upload failed:', err);
}
console.log('Upload successful! Server responded with:', body);
})
var form = r.form()
form.append('my_field', 'my_value')
form.append('my_buffer', new Buffer([1, 2, 3]))
form.append('my_file', fs.createReadStream(path.join(__dirname, 'doodle.png')))
form.append('remote_file', request('http://google.com/doodle.png'))