About
Built because picking one felt wrong
A freeform whiteboard is good for thinking. Diagram-as-code is good for something that has to stay tidy every time it changes. The two rarely live in one place, so people draw everything twice.
The problem being chased
An idea usually starts rough: crooked boxes, arrows that aren't straight, notes in the margin. At that stage, a tool that demands tidiness only slows you down. A few days later the same idea has to be presented, stored, and updated — and at that stage the hand drawing becomes a burden.
Most people solve it by redrawing in a second tool. FlowIcon puts both in the same workspace, with the same colors, fonts, and permissions.
Three decisions that shaped it
The drawing engine is written in-house
The original plan used two mature open-source libraries. Both were dropped, and the sketch engine and the diagram engine were written from scratch on one shared geometry core.
There are two reasons. First, no other party's attribution or watermark may appear in a document a user made. Second, real-time collaboration demands a data model designed to merge per field; wrapping someone else's model only defers that problem until it is too late.
No trackers, at all
No third-party script is loaded on any page — no analytics, no ad pixels, no cookies beyond the ones needed to keep a session signed in. Document contents are not used to train any model. The Privacy Policy names every category of data that is actually stored, rather than a generic list that would fit any application.
Your drawings can leave
Every document exports to PNG, SVG, or PDF from inside the editor, and diagram-as-code is stored as plain text you can copy anywhere.
A format other tools can open is the only guarantee that does not depend on us.
What you can do today
- Canvas and editorTwo modes in one editor: a free canvas for quick sketching, and a tidy mode for diagrams that need to stay straight. It runs in the browser, with nothing to install.
- Real-time collaborationSeveral people on one document, with visible cursors, follow mode, and changes merged field by field instead of overwriting each other.
- Diagram-as-code and iconsA small language for writing diagrams as text with computed layout, plus an icon library of common shapes and the AWS, Google Cloud, Azure, and CloudStack vocabularies.
- Sharing, history, and exportShare links, version history, threaded comments, PNG/SVG/PDF export, and diagrams generated from a sentence.
Built with
Next.js 16 and React 19 on TypeScript, PostgreSQL for data, Redis for caching and rate limiting, Auth.js for passwordless sign-in, and two in-house canvas engines on one shared geometry core.
The handwriting font used across the site is Caveat, licensed under the SIL Open Font License, with its license file kept inside the repository.
Getting in touch
Questions, bug reports, suggestions, and security findings all go through the contact page. Common questions are already answered in the FAQ.