Gaps found in Microsoft Exchange API documentation

Software companies that provide alternatives to Microsoft Exchange, cautiously welcomed at CeBIT last week the recent publication of application programming interfaces for Microsoft volume server products, but have found gaps already in what has been released.

Brian Joseph, chief executive of Zarafa — which makes an email server that is compatible with Outlook, having ported, as he put it, "all the Exchange features to the Linux platform with full MAPI [messaging application programming interface] implementation" — said there are significant gaps in the Microsoft documentation released to date.

Speaking to ZDNet.co.uk at the CeBIT conference, Joseph said Microsoft's start is not promising: "This could definitely make life easier for developers, but we have spotted over 200 undocumented exceptions, including one that allows you to create recurring calendar appointments in Exchange. It was in the documentation for Exchange 2000, but they forgot to document it for Exchange 2003 and Exchange 2007."

Zarafa produces the eponymous email server that runs on Linux and is used by enterprises such as car-rental company Sixt, which recently migrated its entire email server infrastructure to Zarafa. Zarafa uses the MAPI open standard to communicate to email clients such as Outlook. While Microsoft Exchange uses MAPI too, it also uses a large number of proprietary APIs that let the Outlook client perform actions such as creating recurring calendar appointments on the Exchange server.

"I am very positive about unconditional publication of APIs," said Joseph, "but only time will tell if this is justified, given Microsoft's history. I think hundreds of thousands of developers around the world are very interested in full publication with regular updates, but the devil is in the detail; for policy makers, these gaps in the Exchange documentation should put another light on the value of Microsoft's announcement."

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John Robb, vice president of marketing at Zimbra, which produces the Zimbra Collaboration Suite — which also runs on Linux platforms and servers — and runs 11 million mailboxes through the commercial version of its product, and many more through the open-source version, agreed that Microsoft's announcement is a good move, but again expressed reservations.

"The MAPI protocol is open anyway, so that doesn't affect us directly," Robb said, "but we are concerned that Microsoft has not announced which APIs have patent conditions, nor what those conditions are. We're anxiously awaiting details."