What is causing exceeding of Rate Limit in My Program?

Question

I am using the Stackoverflow API to collect the tags in Stackoverflow. I am using NodeJS and am facing a typical problem. My rate limit gets exceeded after 230-250 requests.AS far as I have read it allows <30req/sec . So it should work fine according to my program, but instead I get an exception after 200+ cycles.MY nodejs code is as follows:-

var request=require('superagent');
var request=require('mongoose');
mongoose.connect('mongodb://shivkumarganesh:11111@paulo.mongohq.com:10090/lklklklkkkkl_gshiv_sk');
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function callback () {
  console.log('Connected');
});

//Schema for Tags
var tagSchema = mongoose.Schema({
    name:String,
    count:Number,
    is_required:Boolean
,    is_moderator_only:Boolean,
    has_synonyms:Boolean});

var Tags = mongoose.model('Tags', tagSchema);

var saveSchema = function(Model){
    Model.save();
}
 ///usr/local/lib/node_modules/superagent  
var i=1;
var req=function(){
    request.get('http://api.stackexchange.com/2.1/tags?page='+i+'&pagesize=100&fromdate=1199145600&todate=1377648000&order=asc&sort=popular&site=stackoverflow')
   .set('X-API-Key', 'foobar')
   .set('Accept', 'application/json')
   .end(function(res){
     if (res.ok && i<346) {
       console.log('yay got ' + res.body);
       var jsonResponse = res.body;
       console.log(jsonResponse.items.length);
       for(var j=0;j<jsonResponse.items.length;j++)
       {
           var model = new Tags(jsonResponse.items[j]);
           saveSchema(model);
       }
       i++;
       console.log("Number of Iteration ---- > "+i);
       setTimeout(function() {
           req();
       }, 3000);

     } else {
       console.log('Oh no! error ' + res.text);
       console.log('Processing Over'+i)
     }
   });

}
req();

Please help me to figure this out.If possible please rectify the program. Note: I amusing MongoHQ to store data.

Answer 1

You should read this informative link: https://api.stackexchange.com/docs/throttle

Specifically:

A dynamic throttle is also in place on a per-method level. If an application receives a response with the backoff field set, it must wait that many seconds before hitting the same method again.

So check out the backoff field returned, and wait for that much before doing another request.