Why we build privacy-first mobile apps (and what that actually means)

"We care about your privacy" is the most devalued sentence in software. So instead of saying it, here is exactly what our apps do and don't do.

What "privacy-first" means in practice

Every app store listing claims to respect privacy. The difference is verifiable in the privacy label, so here is ours, spelled out:

• No analytics SDKs. There is no Firebase, no Amplitude, no Mixpanel in our apps. We do not know how long you play, which levels you fail, or what time of day you open the app.
• No ad networks. Ads are the single biggest privacy leak in mobile software — an ad SDK is a data-collection SDK with pictures. Our apps contain none.
• No accounts. You can't sign in to our apps, which means there is no server-side profile of you to breach, sell, or subpoena.
• Local data only. Game progress, scores and settings live on your device. Delete the app and the data is gone — from everywhere, because it never existed anywhere else.
• Offline operation. Bumbi and Numly work with no connection at all. What can't connect, can't leak.

The honest trade-off

Choosing this model costs us things, and it's worth being open about which ones.

We fly blind. Most studios A/B test their difficulty curves against retention dashboards; we tune levels by hand and rely on store reviews and email to hear when something is wrong. We also give up the "free + ads" business model entirely — which is why Bumbi costs $0.99 once, and why Cubepop and Numly are free and simply unmonetized beyond optional purchases. For a two-person-sized studio, the trade is worth it: we'd rather have a small product we're proud of than a funnel we have to apologize for.

How to verify this yourself

Don't take our word for it. On the App Store, open any of our listings and check the App Privacy section — it reads "Data Not Collected". On Android, Google Play's Data safety section shows the same for Numly. And the strongest test needs no store at all: turn on airplane mode and play. Everything works, because nothing was ever leaving your device in the first place.

Our full privacy policies are one page each, in plain language: Cubepop, Bumbi, Numly. If you have a question they don't answer, email us — a human reads it.