Interactive Markdown
Markdown, but alive.
Drag a slider — the document computes, right there. Live charts,
playable simulations, quizzes that grade themselves. And it's still a
plain-text .md file: email it, commit it, keep it for
ten years.
Free forever for reading & writing · Open AINP format · Works offline
Then email it to a friend — that's the whole idea.
Why Rho MD
Your data is yours
Every Rho document is a plain file on your disk. It works offline, needs no account, and can't be locked away. You own it for the long term.
An open format
Rho speaks AINP — an open spec under CC BY 4.0. Anyone can read it, write it, or build their own reader. You're never trapped in one vendor.
Works everywhere
Desktop, mobile, or any browser renders the same document. Email it, commit it, archive it for ten years — it just opens, alive.
Three steps. No platform required.
Write plain Markdown
Add a Rho block — a slider, a chart, a stepper. Your document is still just text in a .md file you fully own.
It comes alive anywhere
Any Rho reader — desktop, mobile, or this browser — renders the block into a live, interactive widget. Nothing to install for readers on the web.
Send it like any file
Email it, drop it in chat, commit it to git. One portable file travels everywhere — and your reader gets the working app, not a screenshot.
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.
PDF, slides, video, plain Markdown. Easy to send and keep — but the bits never change when you look at them.
SaaS dashboards, notebooks, online widgets. They respond — but they live behind an install, an account, a URL that rots.
Rho MD lives here. A single declarative .md that computes for the reader — and still emails, greps, and stores for ten years.
Not a slideshow. Things you can actually poke.
Every panel below is a live Rho document — no video, no embed, no backend. Drag, switch tabs, step through. This is what your readers get.
Where Rho shines.
Interactivity wins decisively whenever the content has variables, cause-and-effect, or steps. These are the documents Rho was built for.
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.
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.
Docs that demonstrate.
Live config builders, tunable API examples, step-through guides, and version timelines — the doc shows the behavior instead of describing it.
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.
.md file.
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.
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
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.
For AI & developers
Your AI already knows how.
AINP — the open format Rho speaks — is CC BY 4.0 and built for language models. Describe what you want in plain language; your LLM writes the document.
“Make an explorable that shows how a bell curve changes as I drag its mean and spread.”
```interact
slider mean range=-5..5 step=0.5 default=0 label="Mean (μ)"
slider sd range=0.5..4 step=0.1 default=1.5 label="Spread (σ)"
template vega-lite: { …a bell curve of the normal density… }
```↑ the exact block behind the bell curve you just played with.
And it goes deeper than generation: the desktop app is AI-native end-to-end — every feature is exposed through a local agent API, so your assistant doesn't just write documents, it can open, edit, organize, and publish them for you.
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.
The core app & renderer. Read and write interactive .md on desktop. Like a PDF reader, but the document is alive.
This site and the in-browser renderer — open and view any Rho document with nothing installed.
rho.md →A WYSIWYG editor where the source is the widget. Author interactive docs without touching syntax.
Coming soonShare by link for free — anyone with the link can view. Publish to the public index, with search and your author page, for $5/mo.
rho.md/cloud →Describe what you want in plain language; get back a working interactive .md. The thing nothing else offers.
Free to use. Pay to create at scale.
Reading, writing, and sharing by link are free forever. You pay only to publish to the world — and, at launch, to author and generate at scale.
- Read & write interactive
.md - Desktop reader + in-browser viewer
- Share by link — anyone with the link can view
- The open
AINPformat, forever
- Publish to the public rho.md index
- Searchable & discoverable by everyone
- Your author page, your audience
- Organize works into collections
- Sync your Psi library across devices
- WYSIWYG authoring without touching syntax
- Generate interactive docs from a prompt
- For people who create & ship, not just read
Questions, answered.
Is it really just a file?
Yes. A Rho document is a plain .md file — open it in any text editor and you'll see normal Markdown with a few fenced blocks. There's no proprietary container, no database row. The file is the document.
Do my readers need an account or an install?
On the web, no — Rho Web renders any document in the browser with nothing to set up. On desktop, the Rho MD reader will be a free download — it’s in final testing now. Reading is always free and never requires an account.
Is the format actually open?
Yes. Rho speaks AINP, published under CC BY 4.0. Anyone can read the spec, write documents, or build their own reader. The format isn't ours to lock — that's the point.
How is this different from Notion or Google Docs?
Those live on a server behind a login — your document isn't a portable file you can email, grep, or keep for a decade. Rho is a file first: it works offline, travels anywhere, and still computes for the reader.
How is it different from a PDF?
Same portability — one file you can send and archive — but a PDF is frozen. Rho documents respond: drag a slider, switch a tab, step through a process, and the page recalculates for you.
Is my data private?
The file stays with you. Rendering never loads network content — that's enforced structurally, not just promised — so opening a Rho document can't phone home. And for documents that are nobody's business, you can password-protect them: encrypted to read, or open to read but locked to edit.
Can my AI assistant use the app?
Yes — by design. The desktop app exposes every command through a local agent API: an assistant can open documents, edit them, organize the library, and publish, using the same commands you do. Rho MD is built to be driven by AI, not just to render what AI writes.