The Google Vision API has a limit of 10 requests per second. I have put a time gap of 10 seconds between each request and even then the response I get for every request after the second or third request is as below. The first request always works just fine.
, https://vision.googleapis.com/v1/images:annotate?alt=json returned "Insufficient tokens for quota group and limit DefaultGroupUSER-100s using the limit by ID ******@*******.
What could be the reason that this is happening. Is there something the documentation that I am missing ?. The images I try to pass are in the range of 100-150 KB size only.
You need to do service authentication take a look at: http://googlecloudplatform.github.io/google-cloud-dotnet/docs/Google.Cloud.Vision.V1/
Note that the default credentials obtained by running gcloud auth application-default login from the Google Cloud SDK are not suitable for use with this API. (They will work initially, but implicitly have a very small request quota.)