OSI-licensed only · self-hostable
Balsamiq is a proprietary wireframing tool known for its deliberately sketchy look. Open-source options cover the same job from different angles: a full design tool, a hand-drawn whiteboard, a diagram editor and a prototyping tool.
Every tool below is under an OSI-approved licence (MPL-2.0, MIT, Apache-2.0, GPL-3.0 or LGPL-3.0), checked against its repository. tldraw is listed separately because its SDK licence is not OSI-approved.
Licences checked against each repository on November 7, 2026.
| Tool | Best for | Licence | Runs as |
|---|---|---|---|
| Penpot | Full design and prototyping | MPL-2.0 | Docker |
| Excalidraw | Hand-drawn style sketches | MIT | Docker |
| draw.io | General diagramming and simple mockups | Apache-2.0 | Desktop app |
| Quant-UX | Prototyping with usability testing | GPL-3.0 | Docker |
| PlantUML | Wireframes as text | LGPL-3.0 | Desktop app |
Best for: Full design and prototyping
A self-hostable design tool for product teams that need collaboration at scale.
Best for: Hand-drawn style sketches
An open-source, collaborative virtual whiteboard for creating hand-drawn-style diagrams and sketches.
Best for: General diagramming and simple mockups
A JavaScript, client-side editor for general diagramming.
Best for: Prototyping with usability testing
A research, usability and prototyping tool to quickly test your designs and get data-driven insights.
Best for: Wireframes as text
Generates UML diagrams from textual descriptions, and its Salt syntax produces wireframe graphical interfaces and UI mockups.
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| If you need… | Start with |
|---|---|
| Replacing Balsamiq for product teams | Penpot |
| Quick sketchy wireframes | Excalidraw |
| Flows and diagrams alongside mockups | draw.io |
| Clickable prototypes with testing | Quant-UX |
| Wireframes in docs | PlantUML |
Public source code, but under licences the Open Source Initiative doesn't approve. Fine to use; read the terms first.
The SDK source is public, but it is provided under the tldraw license and production use requires a licence key, so it is not OSI-approved.
Quick answers to common questions
Balsamiq is proprietary. Excalidraw gives a similar sketch look and Penpot is the fuller open-source design tool.
Excalidraw, because of its hand-drawn style.
Penpot and Quant-UX can be self-hosted; Excalidraw and draw.io can run entirely in the browser.
These tools do not advertise direct import of Balsamiq's file format. Export images or PDFs and rebuild key screens.
Its repository shows a custom tldraw license with a licence key needed for production, so it is not OSI-approved.
List it on TechLogHub and we'll review it for this page.
