Google Cloud Storage is Amazon S3 API-compliant. To use Google Cloud Storage with Dropshare for macOS, follow this steps:
Create a new bucket in Google Cloud Platform. Make sure object-level and bucket-level permissions are enabled.
Next, enable interoperability. Navigate to Settings, and select Interoperability. Select create a new key to create S3 API-compatible access and secret keys.
Open Dropshare for macOS, and create a new S3 API-compatible connection in the connection preferences. Use your bucket name, the access and private key from Google Cloud Platform, and storage.googleapis.com as server address.
Make sure to enable SSL and Path-Style URLs. You're all good!