What is Reactive: your app in one sentence, private by design
Welcome to the Reactive blog. For the first post, let’s start at the beginning: what exactly is Reactive?
A document that becomes an app
Reactive turns a plain text document into a working application — forms, tables, calculations, charts — right in your browser. You write on the left, the app comes to life on the right, as you type. No server, no account, nothing to install: open the page and you’re already working.
The text is Markdown, the same dead-simple format used for notes and
documentation, enriched with small declarative tags: a line like
::input{field="name"} becomes a text field, :::table{path="clients"} a
table with search, sorting and CSV import/export built in. The data you
enter stays in your browser, kept separate app by app, with backup and
restore to a file whenever you want to take it with you.
The assistant that writes it for you
You don’t need to learn the syntax: describe the app you need — “a time sheet for my practice”, “a home budget” — and the AI assistant builds it before your eyes, applying the changes by itself (with Undo always one click away). And the AI can live inside the apps too: summaries that refresh when data changes, forms that fill themselves from a photo, semantic search over your attachments.
The house rule applies here as well: the model runs on your device — in the browser or with Ollama on your computer. No data roaming the world.
You don’t start from scratch: the catalog
The catalog collects ready-to-use vertical solutions — CRM, invoicing, inventory, practice scheduling, school, public offices, everyday life. Each one is a suite of composable micro apps sharing a data space: the client list you enter once feeds quotes, deals and deadlines. Open a suite in one click, keep the pieces you need, customize the rest with AI or by hand.
Collaborating, without giving up privacy
An app is a file: share it with a link and whoever opens it gets a working copy. If you want to work on the same data, turn on sync: changes travel end-to-end encrypted through a relay that only forwards unreadable packets — nobody, not even us, can read what you write. The access key stays on your device and travels only in the invite (a link or a QR code): the file itself never contains secrets.
Why it’s built this way
Privacy in Reactive is not a setting: it’s the architecture. There are no servers holding your data, no accounts to breach, no “us” that can peek. It’s also why the service is free: there’s no infrastructure making you pay with your data or a subscription.
If you want to try it, open the app and write one sentence. If you want to understand how it works underneath, start from the guide. And on this blog we’ll tell, release after release, where the project is heading.