Over the last few months, I've been building Room8, an AI-powered mood tracker that helps people understand their emotions through simple daily check-ins, weekly insights, and a reflective AI companion.
In this post, I want to share why I built it, the technical stack behind it, the challenges along the way, and what I learned shipping an AI wellness product as a solo developer.
Why Build Another Mood Tracker?
I’ve used apps like Daylio, Finch, and Moodflow, and while they're great, I always felt something was missing. They track emotions, but don’t help you interpret them. Weekly insights are usually just simple trend lines. There’s no deeper reflection or guidance. They don’t feel human. I wanted a system that acts more like a supportive companion than a spreadsheet.
So Room8 focuses on three things:
- One-tap mood logging (no friction)
- AI-generated weekly reflections
- A conversation-based reflection experience
You can chat with an AI companion that receives your weekly summary and talks with you about your emotions in real time.
Tech Stack Overview
For those curious about the engineering side, here’s what powers Room8:
Frontend
- React Native + Expo
- Expo Router
- Reanimated & Lottie animations for smooth UI
- MobX for state management
Backend
- User entries are stored on-device for privacy
- No constant server sync
- No cloud database
AI System
- OpenAI Assistants API for weekly summaries
- A custom system prompt that interprets mood logs generates patterns, and provides CBT-influenced reflections
Privacy by Architecture
Many mental-health apps have poor privacy practices, so I built Room8 with:
- Local-only data storage
- No ads
- No behavioral analytics
- No background tracking
- AI chats deleted after closing the session
- You own your emotional data — not me.
Biggest Challenges Building Room8
Making mood logging frictionless
Mood tracking has to be, fast, intuitive and satisfying. I redesigned the check-in screen five times before landing on a UI that works in a single tap.Getting the AI to feel consistent
AI is powerful but unpredictable. I had to create structured internal data formatting, summaries with stable schemas, a limited emotional vocabulary and prompt constraints for tone consistency.
If you got to this point and you're interested, you can check it out on Room8: AI Mood Tracker website and download it both for iOS and Android.
Thank you and cheers :)
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