Open source prototyping projects
Every project in the registry tagged prototyping, ranked by real GitHub adoption.
Open-source UI design and prototyping for product teams
The Pencil Project's unique mission is to build a free and opensource tool for making diagrams and GUI prototyping that everyone can use.
Charm: A Framework for Rapidly Prototyping Cryptosystems
Flexible layout tool for creating UI on any platform
Web based diagramming app that lets you build interactive diagrams and prototypes
Frequently asked questions
How many open source prototyping projects are there?
This registry tracks 5 projects tagged prototyping, with 73,752 GitHub stars between them. The most-adopted is Penpot at 61,995 stars.
Are these prototyping projects free to use?
Yes — 5 of the 5 carry an explicit open-source licence across 4 distinct licences, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.
Which prototyping project should I choose?
The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.
Are these prototyping projects still maintained?
5 of the 5 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.