Yunoa

Most mental health apps are advertising businesses with a journal attached. You write down the worst thing that happened to you this week, and the app takes that as a targeting signal.

Yunoa is the same category of product with that business model removed, which turns out to change nearly every technical decision downstream.

designing around not knowing#

The interesting engineering here is subtractive. Entries are encrypted and stay on the device, so there is no server-side copy to leak, subpoena, or lose. No account is required to write something down — the first entry happens before any identity exists, because asking someone to sign up before they can vent is exactly the wrong order.

No analytics SDK either. That means no funnel, no retention cohort, no crash breadcrumb trail from the screen someone was on when it broke. Every one of those is a real cost, and they're the costs I'm choosing rather than the ones that come out of the user's privacy.

the sync problem this creates#

Encrypt on the device and the easy features get hard. Search across entries, a new phone, a backup that survives a dropped handset — all of these are trivial when the server can read the data and awkward when it can't. Most apps quietly resolve this by holding the keys and calling it end-to-end anyway.

I'd rather ship less and not do that. It's the main reason this one is still marked early.

habits in the same place#

Habits and streaks sit next to the journal rather than in a separate app, because they're the same act. "Did I do the thing" and "how was today" get answered in one sitting or neither gets answered at all, and splitting them across two apps is how both stop being used by week three.