Microsoft has promised sweeping changes that will revamp its position on interoperability but the company is likely to face close scrutiny over how far it lives up to its promises.

The firm said today that it will open up its software and change business practices to allow improved data portability, extend support for industry standards, and work more closely with customers to support popular data formats.

The moves will include documenting APIs and communication protocols with 30,000 pages of information on Windows protocols posted on the MSDN developer site immediately. Microsoft will also rework APIs for Word, Excel and PowerPoint so that other software companies can plug in their document formats and users can elect to make them default “save as” settings.

Steve Ballmer, Microsoft chief executive, said the company‘s “long-term success depends on the ability to deliver a platform that is open and flexible and provides choice”.

Microsoft chief software architect Ray Ozzie noted that the life of modern documents extends “well beyond the lifetime of any application that might have been used to create it”.

On the web, skeptics were quick to doubt Microsoft’s promises but others were more welcoming.

“It’s a big step and a really good step for Microsoft,” said Matt Asay, vice president of business development at open-source enterprise content management firm Alfresco.

“If nothing else the pledge to open up APIs is huge. They’re putting the documentation out there and making it available to everybody.”

Asay added that quality of documentation was a potential issue but said the moves should be a boon for firms trying to provide good interoperability with Microsoft software.

Analyst firm The 451 Group said the steps had "huge implications for customers, competitiors and partners".