Sketch each screen and what it does —its data, its actions— without wasting time on pixels. The fastest way to see your whole product before you build it.
No account · No card · Works offline · macOS
Whatever you don't conceptualize, you patch later.
It doesn't matter if you build with AI, no-code or code: you start with a pile of loose requirements. Until you bring them down to concrete screens —this is a form with these fields, this is a table that shows X— you don't know where each piece of data comes from. And when you want to show something that actually lives in another entity, it's already too late to fix it. Cairn shows it to you during discovery, in an afternoon.
Three steps, all in the same app. No cloud, no account, no friction.
Create nodes (screens) and define what data, roles and operations (create, read, update, delete) live in each one. Without fighting with pixels.
Join the screens into scenarios with connectors and mark the dependencies between flows: what has to happen before what, even across different roles.
Cairn walks the scenario node by node and flags the break: where a screen uses a piece of data that no earlier step created. The gap, before you build.
No other tool does this: Cairn understands what data each screen needs and what data it produces. When you run the scenario, it walks through it step by step and detects when something is used without having been created — like a spell-checker, but for the logic of your product.
Wireframe tools give you boxes and arrows. Cairn understands what they mean: data, roles and dependencies that can be walked through and verified.
Sketch screens (page, modal, sheet) in seconds. Structure, not decoration — the aesthetics come later in Figma.
You declare what is created, read, updated or deleted in each block. Information stops being implicit and becomes part of the design.
Every scenario has a role: who runs it. Model real flows with several actors, even when one role sets up another's work.
Chain screens into navigable flows and mark which action triggers each step — from a table's “Create” button, for example.
Declare the causal order: Login depends on Sign-up, even across different roles. Cairn prevents cycles and warns of broken references.
While you design, Cairn checks that every piece of data a screen uses was created in some step of its causal chain. The error surfaces on its own.
See where each piece of data is used across the whole product, and the complete journey of each role in causal order. Two lenses on the same model.
Everything lives on your Mac, in portable .cairn files. Your projects never leave your machine: no mandatory cloud, no accounts, no lock-in.
They ask you to draw the UI — perfect if you're going to iterate on the design. But none of them let you say “Screen A: a form with these fields” in seconds to understand what each screen does, nor warn you when a flow uses data that nobody created. Cairn doesn't compete on pixels: it competes on making your product work.
| Cairn | Figma | Miro | Balsamiq | |
|---|---|---|---|---|
| Fast low-fi wireframes | ✓ | ~ | ~ | ✓ |
| Data per screen (CRUD) | ✓ | — | — | — |
| Roles / who does what | ✓ | — | — | — |
| Dependencies between flows | ✓ | — | — | — |
| Run the flow (test) | ✓ | — | — | — |
| Catches missing data before you build | ✓ | — | — | — |
| Works offline · your files | ✓ | — | — | ~ |
| Your data never leaves your machine | ✓ | — | — | ~ |
| One-time payment (no subscription) | ✓ | — | — | — |
| Pixel-perfect / high-fidelity design | on purpose, no | ✓ | ~ | — |
| Real-time collaboration | coming soon | ✓ | ✓ | ✓ |
Use Cairn to get the what right; use Figma afterwards to polish how it looks. For Figma or Miro a wireframe is pretty boxes; for Cairn it's a living structure of data, roles and operations that can be run — which is why it finds the hole before a dev does.
Cairn runs on your machine: your projects live in local .cairn files,
with no mandatory cloud or accounts. With Figma or Miro your work lives on their servers; with
Cairn, on yours. Built for sensitive information and for the EU's privacy requirements.
.cairn files
Built for the EU
“I spent 16+ years building products and worked at plenty of agencies, where I saw the same mistake over and over: closing the client without understanding the problem or the product. I tried Figma and Miro to speed up discovery and always ended up fighting the pixels —the client thought we were designing when we were really modeling their idea. So I built Cairn: today we map out an entire app in a single short call, and everyone walks away knowing exactly what gets built.”
No subscription. You buy once and that version is yours for life. Updates are included for one year; after that year you keep using Cairn without limits — you only renew if you want the new versions.
Try it free with no card and no time limit. Activate Pro whenever you want, from inside the app itself.
Cairn is a desktop app for macOS to design your product in minutes during discovery. You create low-fi wireframes and model the structure of each screen —its data, roles and operations (CRUD)— to understand what it does and where each piece of data comes from, then you run the flows like a test to catch the data that's missing before you build.
It's low-fi on purpose. Cairn is for deciding the structure of your product — what data, roles and operations live on each screen — not for polishing pixels. You do that afterwards in Figma, on top of a foundation you already know works.
Figma and Miro draw; neither understands your data or warns you when a flow reads information nobody created. Cairn does: it runs the scenario and flags the gap. They're complementary — Cairn for the what, Figma for how it looks.
Yes. Cairn runs on your machine and your projects live in local .cairn files — they're never uploaded to any server and you don't need to create an account. Ideal for sensitive client information and for the EU's privacy requirements.
It's a one-time payment, not a subscription: it costs less than an hour of a developer's time. A single forgotten piece of data you catch before building already pays for it. And you can try everything for free before deciding.
For now macOS only (Intel & Apple Silicon), native and fast. Windows and Linux are on the roadmap. There's a free plan to try it without paying anything.
No. You download, open and start. To activate Pro you paste your license into the app; that's all.
Start free, no account or card. Activate Pro whenever you want.
Download for macOSIntel & Apple Silicon · macOS 12+ · free to start