I want to use Google ads API, but now Google tells me my project needs to pass Google OAuth verification. I have applied for verification; how long does this verification take ？
Your app might need to go through verification if:
Your app uses any of the sensitive or restricted scopes to request Google User Data. You want your application to display an icon or display name instead of the redirect URL domain on the OAuth consent screen. The number of authorized domains for your apps exceeds the domain count limit for a project. There are changes to the OAuth consent screen after your app has been approved.
Depending on the scope of the information that your app needs this process can take from a few days to a few weeks.
The sensitive scope app verifications are expected to take 3-5 days to account for clarification questions and re-submissions. Note that the restricted scope verification will take longer to complete, likely several weeks. User access to the app for existing approved scopes will not be impacted during the verification process.
Have a look at the Google Oauth verification FAQ wchich may give you a better understanding of the entire process.