Case Study — Selah
A React Native (Expo) mental-wellness app — Supabase/PostgreSQL backend with auth and a Claude API service layer powering CBT-style conversational flows. 90+ active users.
At a glance
Selah is a faith-based mental-wellness app built around CBT — guiding users to identify cognitive distortions and reframe negative thoughts, with an anonymous prayer community at its core. It needed a trustworthy real-time mobile experience: secure auth, private data, and an AI layer that could hold a supportive conversation without feeling robotic.
Full-stack engineer — the React Native (Expo) app, a Supabase/PostgreSQL backend with auth, and a Claude API service layer powering the CBT-style conversational flows.
Built the CBT flow in React Native (Expo) — guided steps that help users identify cognitive distortions and reframe negative thoughts, with personalized Bible-verse recommendations.
Implemented the anonymous prayer room on Supabase/PostgreSQL with row-level security — real-time shared posts and responses where users interact without exposing their identity.
Built the Claude API service layer behind the conversational flows, keeping prompts and API keys server-side and shaping responses to stay supportive and grounded.
Instrumented retention analytics across features. The prayer room drove near-100% 7-day retention, so I cut secondary features and surfaced it as the primary navigation.
Reached 90+ active users and ran a pilot to validate the experience in the field; one cut feature is being reinstated based on usage feedback.
“핸드폰을 보다가 멈추고 기도하게 된 경험은 처음인 것 같다. 너무 좋았다.”
— User feedback during church pilot (“This was the first time I ever found myself praying while on my phone. It felt really good.”)
90+
Active users
~100%
7-day retention on prayer room — users return daily to update and respond to requests
Now
Preparing for launch with monetization
Designing for vulnerable moments raises the bar on every detail — copy, screen transitions, notifications, and especially data privacy and reliability. I treated security (auth, row-level security, private data) and a calm, dependable UX as core engineering requirements, not polish. And narrowing the product to one real workflow — the prayer room — beat building for everyone; the retention numbers made that decision for me.