We use :telemetry to collect usage data per tenant for Supabase Realtime.

We do this for rate limiting but it also makes it very easy for us to attach a listener (https://github.com/supabase/realtime/blob/main/lib/realtime/...) which ships these (per second) aggregates to BigQuery (via Logflare), which then the billing team can aggregate further to display and actually bill people with.