Slack is doubling down on gathering developers to its platform as its rivalry with Microsoft Teams heats up

• Slack, the popular work chat app valued at $12 billion, announced new features to help users take advantage of outside apps without having to leave the interface.
• This is Slack's latest response to the threat posed by chief rival Microsoft Teams, which claimed in July that it had more daily active users.
• Slack's head of developer relations told Business Insider that the company's appeal is that it's an open platform where anybody can build.
• Slack is also building out a developer community and says it has almost 600,000 daily active registered developers designing apps for Slack
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Slack has become a workplace staple at many organizations, across industries, with the company touting that it has 12 million daily active users.

Today at its developer conference in San Francisco, Slack announced a number of new features to help users customize how they use Slack. A big part of those new features is making it easier for developers to build apps that integrate with the service.

Bear Douglas, Slack's director of developer relations, told Business Insider that many of the new features came about after seeing how developers were creatively getting the Slack platform to provide the level of flexibility they needed.

"How are [developers] bending your platform to suit their needs, and how can you meet that need," Douglas said of the reasoning.

These new features make it easier for users to connect to outside applications they may be using along with Slack - for example, Google Calendar. This push for integration with outside apps like Google's, is fueled by Slack's continued rivalry with Microsoft's Teams app, which is bundled and integrated with the Microsoft Office 365 suite of business software.

Douglas said part of Slack's appeal is that it is an open platform that can be custom-tailored to meet any need, no matter how obscure. He also highlighted how Slack's app directory - essentially its app store - is stocked full of many of the most common integrations and tools that a user might need. That includes some Microsoft software, sure, she said, but also from other vendors large and small.

"Some of the software might already have some integration in the app directory, and if it doesn't you have the ability to write it. That makes all the difference," Douglas said. "Our customers should be able to choose the best software that they want to use, and we should make it possible for them to have that experience...and if that includes things like [Microsoft] Onedrive and Outlook Calendar, absolutely, that works for some of our customers."

Microsoft Teams is a workplace communication hub that integrates Office 365. This makes it an appealing option for companies who rely on Office 365 applications like Outlook and Word. In July, Microsoft said its Teams app had 13 million daily active users, which it said put them ahead of Slack.

Earlier in October, Slack announced new daily active user numbers, saying it has 12 million daily active users, a 37 percent increase from a year prior. That's still less than Microsoft Teams, but Slack highlighted its user engagement figures, which it said showed much people like using the app.

Building a community

Slack is answering this rivalry in part by doubling down on the people who build the tools that integrate with Slack. It's been building out a community made up of outside developers building new software and apps for public consumption, and developers within the companies that use Slack.

"Over the last nine months to a year, we've been working on building out our own Slack platform community," Douglas said. She added that Slack is also releasing a certification program for developers who want to develop Slack apps, aimed at growing the community even more.

Slack says it has over 1,800 apps in its app directory, and over 500,000 custom apps were actively on a weekly basis. It also says that it now has almost 600,000 daily active registered developers designing apps for Slack.

For its part, Microsoft has a well established developer community, with several major business applications beyond its own offering Teams integrations.

Here's a rundown on the specifics of the new features Slack announced today:

• A landing page where users can see all of their available Slack apps, and a new home page within those apps to view and interact with the program directly through Slack.
• New windows to help launch and interact with apps directly (like sending a survey or launching an online class directly in Slack).
• A new "actions" button that is accessible anywhere in the app (including in search), to access app integrations anywhere while using Slack (for tasks like submitting expenses and scheduling a meeting).