Our SaaS runs on Google App Engine and sending the logs to BigQuery only takes a couple clicks[1]. From there you can write SQL to summarize the data by referrer, page viewed, etc. Here[0] is a starting point, though you'll need update the `WHERE` clause so it works for your use case.

You get IP and user agent in those logs if you want to roughly track visit to conversion metrics.

0 - https://gist.github.com/mike-seekwell/83ac75c82a943e287a7abe...

1 - https://cloud.google.com/appengine/docs/standard/python/logs