pencil
Pencil is an open-source GUI prototyping and wireframing tool built as a cross-platform desktop application on Electron, offering built-in stencils, multi-page documents, and export to image/PDF formats.
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[](https://opensources.dev/resource/pencil)No licenseLicense unknown or unstated — treat as all-rights-reserved until clarified.
Production readiness
3/5- Actively maintainedCommits in the last 6 months
- No known vulnerabilitiesNot yet scanned
- Clear, usable licenseLicense unknown / unstated
- Proven adoptionWidely used
- Has documentationDocumentation indexed
npm install pencilOur analysis
Pencil is a free, open-source GUI prototyping/wireframing application that runs as a desktop app. It provides built-in shape collections (stencils), multi-page documents, and diagram drawing with export to common formats.
When to use pencil
Good when you need a free, offline, cross-platform tool to sketch wireframes, mockups, and simple diagrams without subscriptions or cloud accounts. Useful for individuals and teams wanting a lightweight desktop prototyping tool with reusable stencil libraries.
When not to
Not a fit for real-time collaborative design (use Figma or Penpot), high-fidelity vector illustration (Inkscape), or modern web-based diagramming with active maintenance (Excalidraw, draw.io). Also poor for developers wanting an embeddable editor library rather than a standalone app.
Strengths
- Free and open source with no account or cloud lock-in
- Cross-platform desktop app (Windows, macOS, Linux) via Electron
- Built-in stencil collections and multi-page tree-structured documents
- Export to PNG/PDF and a portable zip-based .epz file format
Trade-offs
- A standalone application, not a reusable library/SDK to embed
- Development has historically been slow and intermittent; V3 GA timelines slipped
- Migration off the deprecated Mozilla XULRunner runtime was overdue
- No real-time collaboration; UI feels dated compared to modern web tools
Maturity
A long-established project with nearly 10k stars and packaging in some Linux distros, but the V3 Electron rewrite has been under prolonged 'heavy development' with optimistic release estimates. Maintenance activity is sporadic, so production reliance should account for slow updates.
Pencil is an open-source GUI prototyping and wireframing tool built as a cross-platform desktop application on Electron, offering built-in stencils, multi-page documents, and export to image/PDF formats.