groupme.js

var http = require('http');
var https = require('https');
var GROUP = '10237173'; // Get from another API call
var record = [];
function getMessages(token, res, offset) {
  https.get("https://api.groupme.com/v3/groups/" + GROUP + '/messages?limit=100&token=' + token + (offset ? '&before_id=' + offset : ''), function (apiRes) {
    var buffer = [];
    apiRes.on('data', function (chunk) {
      buffer.push(chunk);
    });
    apiRes.on('end', function () {
      var data = JSON.parse(buffer.join(''));
      var render = data.response.messages;
      record = record.concat(render);
      if (record.length < data.response.count) {
        var ms = data.response.messages;
        getMessages(token, res, ms[ms.length - 1].id);
      } else {
        res.write(JSON.stringify(record));
        res.end();
      }
    });
  });
}
// Make an app through GroupMe developer which points to localhost:3000
http.createServer(function (req, res) {
  if (req.url.indexOf('access_token') != -1) {
    var token = req.url.split('=')[1];
    res.writeHead(200, {'Content-Type': 'text/plain'});
    getMessages(token, res);
  } else {
    res.end();
  }
}).listen(3000);