This document lists and describes 20 different wireframing tools. They include both web-based tools, desktop applications, add-ins for other programs like PowerPoint and Firefox, and plug-ins. The tools listed allow users to create wireframes and prototypes using different technologies like Flash, Silverlight, Java, and as desktop applications for Mac and Windows.

1. 20 Wireframing Tools

2. Balsamiq Mockups http://www.balsamiq.com/ Flash-based

3. Mockingbird https://gomockingbird.com/ Web-based

4. PowerMockup http://www.powermockup.com/ Add-In for PowerPoint

5. Pencil Project http://pencil.evolus.vn/en-US/Home.aspx Add-on for Firefox, Open Source

6. Mockup Builder http://www.mockupbuilder.com/ Silverlight-based

7. Mockflow http://www.mockflow.com/ Flash-based

8. MockupScreens http://mockupscreens.com/ Desktop Application (Mac/Windows)

9. iPlotz http://iplotz.com/ Flash-based

10. Axure RP http://www.axure.com/ Desktop Application (Mac/Windows)

11. HotGloo http://www.hotgloo.com/ Flash-based

12. Pidoco https://pidoco.com/ Web-based

13. Protoshare http://www.protoshare.com/ Web-based

14. WireframeSketcher http://wireframesketcher.com/ Plug-in for Eclipse

15. Tiggr https://gotiggr.com/ Web-based

16. inPreso Screens http://www.inpreso.com/inpresoscreens/ Flash-based

17. Justinmind Prototyper http://www.justinmind.com/ Desktop Application (Mac/Windows)

18. FlairBuilder http://www.flairbuilder.com/ Flash-based

19. Mockery http://getmockery.com/ Desktop Application (Mac/Windows)

20. ForeUI http://www.foreui.com/ Java-based

21. GUI Design Studio http://www.carettasoftware.com/guidesignstudio/ Desktop Application (Windows)