Salesforce.com is handing over developer tools to its customers with the launch of its latest quarterly release, Summer ‘07.

The on-demand software pioneer will open up its Apex Code developer environment to Unlimited Edition and Developer Edition subscribers after having spent the year testing the tools for creating Salesforce-hosted programs with 1,200 users.

“Customers can write code that runs on our servers - it’s programming without software,” said chief executive Marc Benioff in a statement.

Customers developing with Apex Code include Cisco, Dow Jones, E*Trade and Borland. Salesforce’s aspiration is that as well as customising core capabilities, developers branch out from customer relationship management (CRM) and salesforce automation to add new functions.

Apex Code received a rapturous reception when it was first made public in October last year at the annual Dreamforce conference. Dell founder Michael Dell called it “a breakthrough”, while Mark Gorenberg of Hummer Winblad Venture Partners said, “Apex changes the rules. I think this is the most important announcement in the history of Salesforce.”

Salesforce product marketing director, Tim Knight, said that “a large financial services company” and “a large networking company” had both developed non-CRM programs using Apex.

“This is about moving from software as a service to platform as a service,” Knight added. “The fact that a software development company like Borland is using Apex tells you a lot.”

Ovum analyst David Bradshaw said systems integrators currently have the most interest in Apex Code for developing “assets” or customisation of Salesforce implementations for their customers.

“The system integrators have been talking for a while about an "asset-based" strategy, meaning having some products or "proto-products" that could be used as the basis for highly specialised implementations," Bradshaw explained. "These would be akin to the system kernels they used to have some years ago before the applications vendors took away this type of business.”

Salesforce’s AppExhange partners that develop add-in programs will also be among early adopters, Bradshaw said, with end-user organisations following later. “My suspicion is that there will be less interest in Apex [among customers] because Salesforce has been selected by them for the current functionality. I suspect a significant minority will make a lot of use of it in the long run, though perhaps not initially,” he added.

Denis Pombriant of analyst firm Beagle Research agreed that Apex Code could be a slow burn at IT shops. “On-demand development and hosting are new markets and [Apex Code] is like any innovation - people might not know they needed it initially but once they've tried it they'll wonder how they did without it,” he said.

With the Summer release, Salesforce is also extending its Sandbox test-bed environment, allowing multiple instances to be deployed so that tests, training exercises and other tasks can be handled at the same time.

Another new feature is Enterprise Intelligent Workflow, allowing customers to create business rules. Other additions include a search-based user interface for mobile usage, a custom report wizard and a customer portal.