What is developer site in SharePoint

Developer site is used by a Visual Studio for deploying and developing the app. You do not need the app catalog site to deploy the solution on developer site because the developer site by default creates an app catalog. When you try to deploy add-in on non-developer site you got "Sideloading of apps is not enabled on this site" and to resolve this you need to enable app sideloading feature on the site.

How to create developer site : 

1. Login in your office 365 credentials and move to office 365 admin center and click on the SharePoint.

2. Now you are at SharePoint admin center by default you are at site collections section. Click on      new – Private site collection .

3. Now fill the Title, Web Site Address and select the  Develoepr Site in template section, selcet time zone and give the name of the Administrator of the site. You can also fill the resource quota, if you want and click on the OK.

4. You can check your site is created.    

Can we deploy the add -in on a non-developer site?

Yes, you can deploy your package on non-developer also but for that you need to enable app side loading feature on your site. But it’s better if you use the developer site for the purpose development and deployment because enabling the app sideloading feature is not secure that’s why it’s not enabled by default on non-developer SharePoint sites.

How to enable app sideloading feature on site? 

To enable the app sideloading feature on the non-developer sites, you can use the below scripts.  

You can use this script on the page load or ready event. This script enables the app loading feature on your site. 

function setFeature(){

'use strict';
var context = SP.ClientContext.get_current();
// This code runs when the DOM is ready and creates a context object which is needed to use the SharePoint object model
var site = context.get_site();
context.load(site);
context.executeQueryAsync(function () {
  site.get_features().add('e374875e-06b6-11e0-b0fa-57f5dfd72085', true, 0);
  context.executeQueryAsync(function () {
    alert('added the developer site feature to the site collection!');
  }, function (sender, args) {
    console.log(args.get_message());
    alert('unable to add the developer site feature to the site collection: ' + args);

  });
}

How to disable app sideloading feature on site? 

function resetFeature(){

'use strict';

var context = SP.ClientContext.get_current();

// This code runs when the DOM is ready and creates a context object which is needed to use the SharePoint object model

var site = context.get_site();

context.load(site);

context.executeQueryAsync(function () {

  site.get_features().add('e374875e-06b6-11e0-b0fa-57f5dfd72085', false, 0);

  context.executeQueryAsync(function () {

    alert('added the developer site feature to the site collection!');

  }, function (sender, args) {

    console.log(args.get_message());

    alert('unable to add the developer site feature to the site collection: ' + args);

  });

}

To disable the app sideloading feature, use the script mention below.

Point to remember:

1. Enabling sideloading feature is not secure.

2. App side loading feature is not intended for production use.