nopCommerce supports external authentication and comes integrated out of the box with facebook authentication. The main aim of providing this feature on the site is to provide convenience to your users so that they don't have to spend time in filling out registration form or have memorize one more new password.
1) Login to your nopCommerce store site as admin and go to administration section:
2) Now, go to: Administration > Configuration > External Authentication Methods

3) Click on the "Configure" link for "Facebook authentication"

4) Now enter the required values and SAVE changes:
- Enter your app ID/API key. You can find it on your FaceBook application page.
- Enter your app secret. You can find it on your FaceBook application page.
For more information, go to: https://developers.facebook.com/apps
5) Now, go back to "Facebook authentication" page and click on "Edit" to ENABLE this feature like this:

6) Save changes and go to the login page of your nopCommerce store site:
