I built an AI journaling app where the AI runs on your phone — no server, no API calls, no subscription to an AI company

Spent \~6 months building this. Here's the honest breakdown.

**The problem I was solving for myself:**
I wanted AI-assisted journaling but every app with AI features sends your entries to a server. Day One, Notion, Reflectly — all of them. Your private thoughts hit someone's cloud the moment you tap "generate insight." I didn't want that.

**What I built:**
**MirrorNotes** — iOS journaling app where all AI runs on-device. Gemma 3 1B. No API calls, no backend for journal data. Works in airplane mode.

**Features:**
\- Daily nudge — AI-generated reflective prompt from your recent entries
\- Weekly digest — patterns across the week
\- Ask — Q&A against your journal history
\- Mood timeline — sentiment trends over time

**Stack**:
\- SwiftData + CloudKit (local storage + sync, Apple E2EE)
\- Gemma 3 1B on-device inference
\- Supabase auth only (Apple Sign In + subscription status)
\- RevenueCat for IAP

**What's working:**
\- The privacy angle resonates immediately when explained
\- On-device AI demo (generate insight in airplane mode) is a strong visual

**What's hard:**
\- 1B model quality ceiling — it's good enough, not amazing
\- iOS-only by architecture (SwiftData locked me in)
\- Marketing a "what it doesn't do" value prop is genuinely difficult

Live on the App Store. Happy to trade notes with anyone building in the local-first or on-device AI space.