Hi guys. I'm trying an A/B experiment using Google Analytics 4. Trying connect with BigQuery, cause is this way I understand the solution, but I can't understand what json file needs here

You need to create a Service Account for Google Cloud. When you do that, it will give you a JSON file to download with credentials.

Hey Tiago, we are going through this now (with Segment/BigQuery) -- Jeremy and Graham updated the docs recently: https://docs.growthbook.io/app/datasources#bigquery

uh, and about this implementation? already released?

Yes, that feature is released. After connecting to BigQuery, it should prompt you for that