Adobe Systems is offering a Flex toolkit for developers building rich Internet applications that extend Salesforce.com's sales management software.

The Adobe Flex Toolkit for Apex, introduced Monday, is for building the presentation layer of applications that would hook to Salesforce.com's Web services application programming interfaces. Apex is Salesforce.com's platform for building software that can piggyback on its online applications. The platform is comprised of a programming language, APIs and tools.

Adobe Flex is an umbrella term for a group of technologies that stem from the software maker's Flash platform, which was originally developed for building Web animation, but has since morphed into a development environment for Internet applications that can behave like desktop software.

Besides providing access to Apex APIs, the new toolkit builds on the platform's embedded mash-up features that allow developers to insert services and content from the Web within the native Salesforce user interface. Among the capabilities the toolkit can add to applications are drag and drop, rich media, and the look and feel of a desktop application.

Applications built with the new tools, like other Flex applications, run in a Web browser with the popular Adobe Flash Player plug in. Software built with the Adobe toolkit can be packaged and redistributed through Salesforce.com's AppExchange, which is an online marketplace for third-party applications that extend Salesforce's software for managing sales and customer information.

The Flex Toolkit for Apex is available through Salesforce.com's developer site.