Pencil

If you're looking for a free and easy to use tool for creating mockups and prototypes, Pencil is definitely worth checking out. It’s open source, which means it’s completely free to use, and it works smoothly on Windows, macOS, and Linux so no matter what system you're on, you can get started right away.

One of the best things about Pencil is its built in stencils. You get access to a wide range of shapes and UI elements right out of the box, including options for desktop, web, and mobile designs. Since version 2.0.2, it even comes with pre installed Android and iOS UI stencils, making it super simple to sketch app interfaces without hunting for extra resources. Whether you're working on flowcharts, wireframes, or full interactive mockups, Pencil has you covered.

And if the built in collections aren’t enough, there’s a whole community out there creating and sharing additional stencils. You can easily find and download these online to expand your design toolkit without spending a dime.

When it comes to sharing your work, Pencil offers flexible export options. You can save your designs as PNG images for quick previews, or even export them as interactive HTML files. That’s right you can add clickable links and buttons to your prototypes, making it feel like a real app when you present it to clients or teammates. It’s a game changer for demonstrating user flows and interactions.

Plus, Pencil supports exports to formats like OpenOffice, LibreOffice, SVG, and PDF, so you can easily integrate your mockups into documents, presentations, or further refine them in other design tools.

All in all, Pencil is a lightweight yet powerful tool that’s perfect for designers, developers, or anyone who needs to visualize ideas quickly and effectively.