Question: How do I do a POST to an external public form on another site using nodejs and expressjs after constructing a string with the data I want to POST to the form?

I can't find a straightforward example or documentation for this, only keep finding how to handle and parse POST-ing to a form within your own app.

Answer: 
Node.js makes this very easy and it's in their official documentation.

<http://nodejs.org/api/http.html#http_http_request_options_callback>

```
var options = {
  host: 'www.google.com',
  port: 80,
  path: '/upload',
  method: 'POST'
};

var req = http.request(options, function(res) {
  console.log('STATUS: ' + res.statusCode);
  console.log('HEADERS: ' + JSON.stringify(res.headers));
  res.setEncoding('utf8');
  res.on('data', function (chunk) {
    console.log('BODY: ' + chunk);
  });
});

req.on('error', function(e) {
  console.log('problem with request: ' + e.message);
});

// write data to request body
req.write('data\n');
req.write('data\n');
req.end();

```
Since question asks about submitting a form, I thought formatting request body is also a concern. You can encode your form yourself; but also use other libraries for convenience.

<https://github.com/mikeal/request/> is a good one that is very easy to use.