Pencil Project

Pencil Project is a free, open-source desktop application for making GUI mockups, wireframes, and diagrams. It suits designers, developers, students, and teams that want a local tool without a subscription. Its broad stencil coverage and export choices make it a capable starting point, although teams needing hosted collaboration or advanced product-management workflows should look elsewhere.

Overview

Pencil focuses on visual planning rather than finished interface production. Built-in collections cover desktop, web, Android, and iOS controls, while diagram shapes and connectors handle flowcharts and related maps. That combination lets one document move from rough screen layout to basic process explanation without switching applications.

The application is published under the GNU General Public License version 2. Evolus also describes a commercial source-code license, which may matter to organizations with proprietary redistribution requirements. The latest stable release is version 3.1.1, identified as containing stability fixes and new features. Nightly development builds are explicitly unstable, so production work should stay on stable releases.

Key features

Interface stencils and diagrams

Collections for desktop, web, Android, and iOS provide platform-specific starting points instead of forcing every control to be drawn from generic boxes. GUI mockups, wireframes, desktop UI, web UI, Android UI, and iOS UI are all supported diagram types. Connectors and flowchart shapes add enough structure for user flows and system diagrams, making Pencil useful when a project needs both screen sketches and explanatory charts.

Interactive documents and clipart

Elements can link to pages within the same document. In web exports, those links become hyperlinks, so a prototype can demonstrate navigation rather than merely show static screens. The clipart browser integrates with OpenClipart.org and accepts vector artwork by drag and drop, expanding the built-in vocabulary for illustrations and annotations.

Exports and add-ons

Drawings can be exported as PNG images, web pages, OpenOffice or LibreOffice text documents, Inkscape SVG, and Adobe PDF. This range covers quick sharing, editable office handoff, vector work, and printable review packs. Stencil collections and export templates can be installed as add-ons, giving specialized projects a way to extend the base installation.

Pricing

There is no trial period because the product is free, and no paid tier, seat charge, quota, or renewal term is stated. That makes Pencil straightforward for individual work, education, and budget-sensitive teams. The trade-off is that there is no commercial plan offering hosted services or extra organizational controls; users who need those should compare paid or freemium alternatives.

Platforms

Pencil runs on Linux, macOS, and Windows. Downloads include Fedora and Ubuntu builds, support for other GNU/Linux distributions, Windows packages, and a universal macOS DMG for both Intel and Apple Silicon. The downloads page also provides a SHA-1 checksum link, useful for verifying installers before deployment.

Who it's for

Choose Pencil for local-first wireframing, interface planning across major mobile and desktop platforms, and diagram work that benefits from clickable page links. It is particularly suitable when export flexibility and zero software cost matter more than browser-based teamwork. It is less suitable for organizations seeking a managed collaboration service, since the product is presented as a desktop application and its free plan has no stated team workspace features.

Pros and cons

• Pro: Platform-specific stencils for desktop, web, Android, and iOS speed up realistic early layouts.
• Pro: Links between document pages survive as hyperlinks in web exports, enabling a navigable prototype.
• Pro: PNG, web, office-document, SVG, and PDF exports support varied review and handoff needs.
• Pro: Free, open-source licensing removes subscription and seat-cost barriers.
• Con: It is a desktop tool, so readers wanting browser-based collaboration should consider another category of product.
• Con: Nightly builds are unstable and carry an explicit risk warning; cautious users should use the stable release.
• Con: The commercial source-code license is separate from the GPLv2 publication, which may require legal review for proprietary redistribution.

Alternatives

For a wider category view, browse Wireframing Software, Web Design Software, Prototyping Software, UI design tools, Game UI Design Software, or Diagram Software.

Fluid UI is the better choice when you want a freemium service spanning web, mobile, Linux, macOS, and Windows, with a free account and trial-backed paid plans. Pick Mockplus for a freemium option whose Basic plan allows 10 users, 10 active projects, unlimited designs, three project folders, and one admin. Justinmind fits teams wanting interactive UI design and wireframing with one free project and unlimited screens and viewers.

Quickmock is worth choosing when a free, open-source project with an MIT license is the priority. Frame0 offers a no-time-limit free tier with all built-in shapes and 1,500 icons for users who prefer a freemium desktop product. MockFlow suits users wanting a free browser-and-desktop option with one editor and five reviewers. Banani is aimed at web users comfortable with a credit-based free plan, while Draftium is a fit for web prototyping capped at three free prototypes.

Verdict

Choose Pencil Project if you want a no-cost, open-source desktop wireframing and diagram tool with platform-aware stencils, clickable page flows, and unusually broad export support. Look elsewhere if your priority is hosted collaboration, shared team administration, or a managed prototyping workflow rather than a local application.