20 tools for creating wireframes and mockups of user interfaces.

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)