The Vaadin Framework was not written overnight. After working with web user interfaces since the beginning of the Web, a group of developers got together in 2000 to form IT Mill. The team had a desire to develop a new programming paradigm that would support the creation of real user interfaces for real applications using a real programming language.
The library was originally called Millstone Library. The first version was used in a large production application that IT Mill designed and implemented for an international pharmaceutical company. IT Mill made the application already in the year 2001 and it is still in use. Since then, the company has produced dozens of large business applications with the library and it has proven its ability to solve hard problems easily.
The next generation of the library, IT Mill Toolkit Release 4, was released in 2006. It introduced an entirely new AJAX-based presentation engine. This allowed the development of AJAX applications without the need to worry about communications between the client and the server.
IT Mill Toolkit 5, released initially at the end of 2007, took a significant step further into AJAX. The client-side rendering of the user interface was completely rewritten using GWT, the Google Web Toolkit.
IT Mill Toolkit 5 introduced many significant improvements both in the server-side API and in the functionality. Rewriting the Client-Side Engine with GWT allowed the use of Java both on the client and the server-side. The transition from JavaScript to GWT made the development and integration of custom components and customization of existing components much easier than before, and it also allows easy integration of existing GWT components. The adoption of GWT on the client-side did not, by itself, cause any changes in the server-side API, because GWT is a browser technology that is hidden well behind the API. Also themeing was completely revised in IT Mill Toolkit 5.
The Release 5 was published under the Apache License 2, an unrestrictive open source license, to create faster expansion of the user base and make the formation of a developer community possible.
IT Mill Toolkit was renamed as Vaadin Framework, or Vaadin in short, in spring 2009. Later IT Mill, the company, was also renamed as Vaadin Ltd. Vaadin means an adult female semi-domesticated mountain reindeer in Finnish.
Together with the Vaadin 6 was released the Vaadin Plugin for Eclipse. The initially experimental version of the visual editor, which was included with the plugin, has since then grown into to stable development tool.
With Vaadin 6, the number of developers using the framework really exploded. The introduction of Vaadin Directory in early 2010 gave it a further boost, as the number of available components multiplied almost overnight. Many of the originally experimental components have since then matured and are now used by thousands of developers. In 2012, we are seeing tremendous growth in the ecosystem around Vaadin. The size of the user community, at least if measured by forum activity, has already gone past the competing server-side frameworks and even GWT. Whether Vaadin is already past the tipping point can be seen soon.
More technical details about the history of Vaadin can be found from the Release Notes of each version.