The app, and the family around it.

One open format, one free desktop app to live in — and a family of services that grow out of the same plain .md file.

Every other format makes you pick one.

Files are portable but frozen. Apps respond but need a server and a login. Rho MD is the only thing that's both.

Fixed & portable

PDF, slides, video, plain Markdown. Easy to send and keep — but the bits never change when you look at them.

Responsive, not portable

SaaS dashboards, notebooks, online widgets. They respond — but they live behind an install, an account, a URL that rots.

Responsive and portable

Rho MD lives here. A single declarative .md that computes for the reader — and still emails, greps, and stores for ten years.

Where Rho shines.

Interactivity wins decisively whenever the content has variables, cause-and-effect, or steps. These are the documents Rho was built for.

Teaching & explainers

Don't explain the formula — let them feel it.

Drag-to-learn explorables for math, finance literacy, physics, statistics. The reader builds intuition by manipulating, not watching.

Data & finance reports

What-if, not just what-is.

Readers plug in their own assumptions and the report recomputes for them — projections, models, pricing, scenarios. One file, every scenario.

Product docs & changelogs

Docs that demonstrate.

Live config builders, tunable API examples, step-through guides, and version timelines — the doc shows the behavior instead of describing it.

Dashboards in a file

A dashboard you can email.

Metrics and charts that compute locally — no BI login, no broken link next quarter. Send the numbers and the controls in one .md.

More than a reader.

The free desktop app is where your library lives — edit in place, organize visually, lock what's private. All of it stays plain .md on your disk.

The Rho MD desktop app, dark theme: a solar-system document with outline, file tree and calendar in the sidebar, and a live orbital simulation computed from the markdown itself.
The actual app — a solar system simulated live from a plain .md file.
Edit mode with the source slider at raw Markdown: the document's plain-text source in a code editor.

Edit in place

WYSIWYG-lite editing for your text, with a slider down to raw Markdown when you want the source. Common syntax converts as you type.

Psi's 3D star map: documents as blue stars clustered around orange folder hubs on a dark background.

A star map of your library

Psi, the built-in document manager, lays your docs out as a galaxy — related documents cluster together. Double-click a star to open it.

A freeform canvas mind-map with colored linked nodes, saved as a plain markdown file.

A freeform canvas

Think on an infinite board — drag notes, link ideas, drop in documents. It saves as a plain .md file, like everything else.

Lock what's private

Password-protect any document: encrypt it so reading needs the password, or keep it readable and require the password only to edit.

Plugins, done right

A clean plugin API — with official calendar and pomodoro plugins — built on the same registry the app's own features use.

AI-native to the core

Every command — open, edit, organize, lock, publish — is exposed through a local agent API. Your AI assistant can drive the whole app.

One format. A family of ways to use it.

Reading and sharing are free — that's how Rho spreads. Creating at scale, syncing, and AI generation are where Rho earns its keep.

Make your next document do something.