Set application authentication OAuth 2.0 for Blogger API v3

When your application is requesting to access private data, the request must be authorized by an authenticated user using sensitive information who has access to that data. Whereas your application requests public data access, the request does not have to be compelled by authentication, such as an API key.

1. Log in your Google account.

2. Go to: https://cloud.google.com/console#/project
Click Create Project.

3. Fill basic information Project Name, Project ID (refresh to change), check checkbox “I have read and agree to all Terms of Service for the Google Cloud Platform products”. Then click Create Button.

4. Click on “APIs” option the left side tab of APIs & auth. 

5. Find the “Blogger API v3” in Browse API option and Enable it. 

6. Click on Blogger API v3 and Explore this API, this will open services tab.

7. Then there will be the Quota Request application (OAuth 2.0), top right side corner Enable it.

8. And then enable both checkboxes and click Authorize button.

You have done.