Pencil

Pencil is an easy-to-use, open-source tool for creating GUI prototypes and diagrams with drag-and-drop simplicity. It includes built-in stencils and templates for web and mobile interfaces, allowing users to quickly design and prototype without technical skills.

The platform supports exporting designs to various formats like PNG, PDF, and HTML, and features like linking pages for interactive flows enhance its utility for low-fidelity prototyping and diagramming across platforms.

Key features

• Wireframing and Mockups: Quickly create mockups for apps and websites with built-in stencils and templates.
• Drag-and-Drop Interface: Easily design prototypes without any technical skills.
• Multi-Format Export: Export designs to PNG, PDF, SVG, or HTML for easy sharing and collaboration.
• Interactive Prototypes: Create interactive UI flows by linking multiple pages.
• Built-in Shape Libraries: Includes pre-defined UI elements for web, mobile, and desktop interfaces.
• Cross-Platform Compatibility: Available on Windows, Linux, and macOS.
• Customization Options: Users can extend the tool with custom shapes and templates.
• Open Source: Completely free and open-source, with community support and contributions.

Best use cases

• UI and UX Prototyping: Ideal for creating low-fidelity prototypes and wireframes for web and mobile apps.
• Diagramming: Great for creating flowcharts, organizational charts, and other diagrams.
• Design Collaboration: Excellent for teams needing to share and review mockups quickly across formats.

Pros & Cons

• ✅ Free and open-source.
• ✅ Simple and intuitive drag-and-drop interface.
• ✅ Supports a wide range of export formats.
• ✅ Built-in templates for web and mobile UI designs.
• ✅ Cross-platform compatibility.
• ❌ Lacks advanced features compared to premium tools.
• ❌ May not be suitable for high-fidelity designs.
• ❌ Limited support for real-time collaboration.
• ❌ UI elements library is not as extensive as in commercial software.
• ❌ Can feel slow or limited for large, complex projects.