I think Google Spanner wasn't available yet that time. They chose GCP for the container support / Kubernetes. There's an interesting talk about this by Niantic

I think Google Spanner wasn't available yet that time. They chose GCP for the container support / Kubernetes. There's an interesting talk about this by Niantic Director of Engineering: https://www.youtube.com/watch?v=j6ARungTOL4 https://www.youtube.com/watch?v=j6ARungTOL4 Timestamp for the part about the launch: https://youtu.be/j6ARungTOL4?t=1249 https://youtu.be/j6ARungTOL4?t=1249 TLDW: Niantic made a prediction on the server load, provisioned 5x of that, and only planned to Beta release in Australia & NZ, but everyone ended up sharing the APK worldwide. The first few weeks of traffic ended up being 50x the initial estimate. Niantic also found some scaling bugs in the game that were fixed in the first weeks. Pokemon Go reached the number of Twitter daily user within 2 days. The next version of Pokemon Go could really benefit from Spanner if they haven't used it already.