Thanks! And agreed, session replays can be really useful to understand user behaviour such as product edge cases.

On cost, it's running the collector Node app (I'd expect a few $ per month at low volume), and the S2 stream backend.

If you use the S2 cloud service, cost is basically just the rrweb bytes. The rates are $0.075/GiB to write, $0.05/GiB-month to store, $0.10/GiB to read back over the internet. See s2.dev/pricing.md for an agent-friendly summary.

Assuming a typical few-minute session is ~1 MiB of events, ingesting it, storing it a month, and replaying it a couple of times (unlikely!):

1k sessions/mo ≈ $0.35

10k sessions/mo ≈ $3.50

100k sessions/mo ≈ $35