(Bloomberg) -- Microsoft Corp. officially rolled out its Teams workplace-collaboration software, counting on integration with its ubiquitous Office and Outlook programs and partnerships with popular business software makers such as SAP to challenge Slack Technologies Inc. for big corporate customers.

Teams, in preview mode since November, is now widely available in 181 markets, Microsoft said Tuesday. Already 50,000 Office 365 customers, including Expedia Inc. and Alaska Air Group Inc., have started trying it. Expedia has its 300-person information technology group using Teams to chat, share presentations and hold teleconferences.

"I really appreciate the tight integration with Office 365," said Armand Campo, senior director of information technology for online travel-booking service Expedia. Campo said he also likes that the software works equally well on a Mac and a PC. While the company will offer Teams to about 18,000 employees starting in the second quarter, some also use rival products like Slack and Atlassian Corp.'s HipChat, he said.

Redmond, Washington-based Microsoft needs to do well in this fast-growing market because a sizable part of corporate email traffic -- where the company dominates -- is moving to chat, where Slack and HipChat were pioneers. More importantly, Microsoft sees Teams as a way to push more of its clients to switch from traditional, on-premise Office software to the subscription-based cloud version, Office 365. Cloud software provides Microsoft a more regular revenue stream and greater sales over time, the company said. Teams is available only to paying customers of Office 365. 

"We can do more for our customers in the cloud than on-premise," said Rajesh Jha, whom Chief Executive Officer Satya Nadella tapped to run the Office group in September. Jha said the new program is speeding up the switch to Office 365 for some customers. When clients see Teams and weigh the pros and cons, they say, ``probably I should move sooner rather than later," he said.

Teams has several design elements that are different from Slack's, including the ability to put different applications and tasks in tabs located across the top of the screen. For example, users can add a tab that takes then directly to their Excel spreadsheets or third-party apps like Zenefits human-resources software and Polly, a service that collects data via recurring employee polls.

Outside companies can also build chatbots for Teams, like they can for Slack, or direct content from their programs to flow directly into discussions so users can have things like tweets appear in their chats. SAP SE's SuccessFactors and Atlassian Corp.'s Trello are also working with Microsoft to let data from their programs be viewed and shared in Teams. 

Since the preview, the company has added 100 new features, such as making it easier to schedule meetings. Microsoft is planning to add about 100 more in the next three months, including allowing guest access for users outside the company. Future upgrades will improve integration with Microsoft's Outlook email program.  

"Unlike Slack, we don't believe email is going to die or that our job is to eliminate it," said Brian MacDonald, one of Teams' two co-creators. ``It may need to be right-sized because it is being used for things it was never intended for."

Slack, meanwhile, has made its own changes to become more competitive in wooing the massive customers Microsoft is targeting. In January, it introduced Enterprise Grid, a version of its popular product designed for companies with thousands of workers. 

MacDonald and Teams co-creator Mira Lane also focused on enabling clients to add and customize short video clips and cartoons, making it easy enough for older users and also appealing to younger ones. Many of Microsoft's enterprise customers are trying to cater to workforces that span four different generations, Lane said. One accomplishment the creators were particularly proud of: they got Nadella to use Giphy, a library for finding animated .gif files, which he mainly employed via Teams to send "good work"-type messages to the development group, Lane said.

So far Teams' main rivals say the competition from Microsoft isn't hurting them.  "Slack created this category and we’re confident in the caliber of our product," the company said in a statement. "It’s not surprising that there are other entrants to the space: the business opportunity is huge."

HipChat also said it hadn't seen any impact. "We have not heard from any of our customers that they are testing out the beta of Teams," HipChat General Manager Steve Goldsmith said in a statement. ``Teams -- like the whole Office suite -- is handed down from IT to their users," he said. "The actual team doesn't really have much say in purchasing or evaluating it.''

But what HipChat sees as a flaw, Microsoft sees as an advantage. 

"The real numbers are not in being used by 10-person dev teams in Silicon Valley -- they're in being used for the world's largest enterprises," MacDonald said. "And those people are on Office already."