Twitter has launched live-streaming video app Periscope, developed by the startup it bought earlier in 2015 for a reported $100 million, upping the battle with overnight mobile-app streaming sensation Meerkat.

“We think it’s a perfect complement to Twitter, which is why we acquired the company in January,” VP of product Kevin Weil wrote in a blog post Thursday.

The Periscope app is available as a free download for iOS devices from Apple’s iTunes Store. The launch of Periscope comes after Twitter in January upgraded its mobile apps to let users capture, edit and post videos — up to 30 seconds in length — complementing the company’s six-second looping Vine clips.

The sudden mania for live-streaming personal video comes after Twitch last summer shut down Justin.tv, one of the first live-streaming video services on the Internet. Meerkat, which launched last month, quickly captured the attention of the digerati — providing a simple, instant way to broadcast live video to followers. (Twitter responded by cutting off the Meerkat app’s access to the Twitter social graph service.)

See More: Meerkat Madness: The Lure of the App du Jour

Separately, Meerkat has reportedly raised $12 million in additional funding led by venture-capital firm Greylock. Other investors in Meerkat include YouTube founder Chad Hurley; Jared Leto; Sound Ventures; Comcast Ventures; Universal Music Group; Raine Ventures; Lorne Michaels’ Broadway Video; WME; CAA; and UTA.

The Periscope app, according to the company, lets users push a button — and inform followers on Twitter that they’re live-streaming video. “We wanted to build the closest thing to teleportation,” the Periscope team writes in a blog post. “A picture may be worth a thousand words, but live video can take you someplace and show you around.”

How Periscope or Meerkat will make money, though, remains in question. Neither company has explained the business model for live-streamed video. But already, Meerkat has attracted high-profile experimenters including Jimmy Fallon, host of NBC’s “The Tonight Show Starring Jimmy Fallon,” who has used the service to broadcast behind-the-scenes segments from his show.

Twitter’s new Periscope app could be a long-term “positive game-changer for the company,” Rosenblatt Securities analyst Martin Pyykkonen wrote in a research note Thursday.

“Periscope enables live streaming video from mobile and other devices, which effectively can mean personalized live video content delivery over the Twitter platform,” Pyykkonen wrote. “We think this could have profound implications for usage/engagement on Twitter and be one other challenge for traditional linear media delivery, as users would spend more time selectively watching live-streaming video from people and subjects that they follow as part of their Interest Graph.”

According to Twitter, Periscope requires iOS 7.1 or later and is optimized for iPhone 5, iPhone 6 and iPhone 6 Plus. When a live broadcast is over, users can make it available for replays for up to 24 hours. In addition, the Periscope app tracks how many “hearts” (favorites) each broadcast receives from followers.