About Ensō

What Ensō is

Ensō (pronounced "en-so", written with a macron over the o) is an offline-first personal productivity suite: todo, agenda, calendar, reading list, projects, notes, email, and history in one tabbed app. It runs on the web at app.ensoapp.io, as a Windows and macOS desktop app, and on iPhone and Android. Every device keeps a full local SQLite copy of your data and works with no connection at all; when you're online, your devices sync through your account every 15 seconds using one shared Rust merge engine, so edits made offline on two devices always converge the same way. Any list, calendar, project, or notes folder can be locked in an end-to-end encrypted Vault that the server cannot read, and your whole account can be exported at any time.

Ensō Premium costs $8 per month or $80 per year, and every new account starts with a 14-day free trial with no card required. Ensō launched in 2026 and is developed and operated by Raintree Forge LLC, an independent software company in Missouri, United States. The name comes from the ensō, the hand-drawn circle of Japanese calligraphy: one stroke, the whole picture.

How it's built

The user interface is one React codebase shared by the web app, the desktop apps, and the mobile apps. Underneath it is a Rust data layer: native SQLite on desktop and mobile, SQLite compiled to WebAssembly in the browser, and the same Rust conflict-resolution engine on every platform, so no client ever re-implements how changes merge. The sync server keeps an append-only log of changes per account and is the ground truth all devices reconcile against. The engineering details are covered on the blog and in the sync & offline guide.

Where your data lives

On your devices, first. Each one holds a complete, readable database; the server holds a synced copy so your other devices can catch up, plus ciphertext for anything in a Vault. You can export a complete snapshot of your account as one zip file from Settings and import it into any account, and deleting your account erases the server copy. The privacy policy names every third party involved, and the your data guide explains export, import, and storage.

Contact

Email contact@raintree.dev for anything — support, press, or questions about the company. See the support page for the fastest routes to help, the FAQ for common questions, and pricing for plan details.