gistfile1.txt

        	// Loop through 
    	for(Integer i = 0; i < contacts.size(); i++){
    		
    		c = contacts.get(i);
    		if(oldAccountIds != null)
    			oldAccount = oldAccountIds.get(c.Id);
    		else
    			oldAccount = null;
    		
    		items.add(new Map<string, object>{ 
    			'method' => 'post', 
    			'data_type' => 'user', 
    			'data' => getIntercomUserFromContact(c, mappedFields, oldAccount)
    		});
    		
    		listIdx++;
    		if(listIdx == 100){
    			listIdx = 0;
    			resp = sendRequest(USERS_ENDPOINT_BULK, 'POST', request);
    			request.put('job', new Map<String, String>{ 'id' => (String)resp.get('id') });
    			items.clear();
    		}
    	}
    	
    	if(items.size() > 0)
    	{
    		sendRequest(USERS_ENDPOINT_BULK, 'POST', request);
    	}
    
    
    private static Map<String, Object> sendRequest(String endpoint, String method, object request){
    	
    	string jsonContents = Json.serialize(request);
    	
    	// Build the request
    	HttpRequest req = new HttpRequest();
    	req.setMethod(method);
    	req.setEndpoint(endpoint); 
		req.setTimeout(60000);
		
		Blob headerValue = Blob.valueOf(APP_ID + ':' + API_KEY);
		String authorizationHeader = 'Basic ' + EncodingUtil.base64Encode(headerValue);
		req.setHeader('Authorization', authorizationHeader);
		
		req.setHeader('Accept', 'application/json');
		req.setHeader('Content-Type', 'application/json');
		
		req.setBody(jsonContents);
		
		// create the client	
    	Http h = new Http();
    	System.debug(Logginglevel.INFO, 'Sending request: ' + req.toString() + ' with data: ' + jsonContents);

    	try{
    		
	    	HttpResponse resp = h.send(req);
	    	
	    	String respBody = resp.getBody();
	    	System.debug(Logginglevel.INFO, 'Received response: ' + respBody);

	    	return (Map<String,Object>)Json.deserializeUntyped(respBody);
	    	
    	}catch(Exception ex){
    		System.debug(Logginglevel.ERROR, ex.getMessage());
    		
    		return null;
    	}
    	
    }