Slownotes
Half the interface isn't on a screen - a note system designed at pen speed.
Scan a page of handwriting and Slownotes turns the ink into structured, searchable notes, ready for Obsidian, Notion, or as context for ChatGPT and Claude. The idea, and the Slowdown markup language at its heart, belongs to the app’s maker. I designed the product around it: the app, the flows, and the way a page of ink becomes something you can search. The defining constraint sat entirely outside my reach: half the product happens on paper, while you write.
Role
Product Designer
launch
2026
Scope
UX/UI, Design System
Scale
Complete AI-implementation
Live
The Challenge
Handwriting offers no affordances: no buttons, no autocomplete, no undo. Slowdown solves the input side with a small set of symbols written straight into your notes, but that puts the full weight of the experience on the app. Everything the pen can’t do, the screen has to: show what the AI understood, forgive what it didn’t, and give the notes somewhere useful to go. And it has to do that for people who chose paper precisely because they don’t want another app in their life.
The Design
Slowdown, a markup language for handwriting.
A small set of symbols adds structure while you write: # for tags, @ for people, + for discoveries, * to trigger AI enrichment. Small enough to remember without looking anything up, distinct enough that the AI never has to guess. The whole language fits on a sticky note, which is the point.
Forgiving by design.
Symbols get written badly, quickly, in margins. The system degrades gracefully: a missed or mangled mark becomes an ordinary note, never an error. Scanning had to feel like the easiest step of the day, because it competes with simply not scanning at all.
A screen that stays quiet.
The app does the processing and hands your thinking back clean and connected. Nothing in it is designed to pull you back in; the only reason to open Slownotes is your own notes, and that is deliberate.
Built to hand your thinking onwards.
Notes sync to Obsidian and Notion, or travel as context into ChatGPT and Claude. Slownotes isn’t trying to be where you live. It’s the bridge between the page and wherever your thinking goes next.
Where it stands now
Live on the App Store, and the paper still works without it.
On the App Store since 2026. The interface was never the hard problem. The hard problem is making a digital product worth it for people who love the pen, whose whole point is not needing one more app. That question shaped every decision above, and I don’t think it ever finishes being answered.
Contact
Want to ship products together?
I'm looking for a team where design doesn't stop at handoff. If that sounds like yours, I'd like to hear about it.
Send me a message at martijnruitenbeek@gmail.com
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