On-device AI, built for privacy.
Rainletter is a software studio based in California. We build apps that run AI entirely on your device — no servers, no data collection, no compromises on privacy.
AI should work for you without watching you. The most personal tools — the ones that hold your thoughts, your routines, your reflections — deserve an architecture where your data never leaves your hands.
We design for that architecture from the ground up. Not as a feature toggle, not as a marketing claim, but as the foundation everything else is built on. If the AI can't run on your device, we don't ship it.
A private AI journal for iOS. Write, reflect, and track your moods — with an on-device AI agent that helps you think, entirely offline. Coming soon to the App Store.
Questions, partnerships, or just want to say hello — reach us at yoki@rainletters.com.