Most mobile analytics tools give you more features. True. But they also ask you to trust closed code and opaque infrastructure. Fantasma takes a narrower approach: it's open source, install-scoped, and built around the few reports most people actually look at. The SDK does not track users and does not let you attach arbitrary user attributes to a session. Each install gets a random identifier. That is enough to understand how an app is doing without collecting more than you need.
I built useFantasma because I couldn't find a good mobile analytics solution that would a) preserve my users privacy and b) I knew what was happening under the hood. Moreover, solutions out there besides having bloated SDKs (yes, I am looking at you Firebase), provide metrics I don't care about.
Taking inspiration from useFathom, I kept both the SDK and the metrics deliberately narrow. I have now shipped it in my own iOS app, Dash, and I am excited to see whether this approach resonates with others too.
The SDKs and backend are open source. It runs well on a small machine (I am able to ingest 60k events/s). It has a CLI that you can use to query your own metrics in your server. So an agent is able to quickly query it without too much trouble. If you don't want to host, you can try useFantasma.com for free.
Dash