You need a service account in order to access some of the Google APIs. A service account is an account that belongs to an application, such as Etlworks Integrator, instead of to an individual end user. The application calls Google APIs on behalf of the service account, so users aren't directly involved. This scenario is sometimes called "two-legged OAuth," or "2LO." (The related term "three-legged OAuth" refers to scenarios in which the application calls Google APIs on behalf of end users, and the user's consent is sometimes required.)
A service account is not the same as an account used to log into Google services from a web browser.
Read more about Google Service accounts.
Etlworks Integrator already has a service account that can be used to access Google APIs. This account is linked to the email address:
You can create your own service account if you prefer to use your own, instead of the default.