Shares of the Santa Monica, Calif., photographic-app maker at last check were up 4.2% to $12.35.
App Stories enables developers to leverage Snapchat’s technology and community of 218 million people.
Initially App Stories will be available on social apps Triller and Octi, video-calling app Squad and dating app Hily.
Snap VP of Partnerships Ben Schwerin said the company is looking to bring App Stories to more partners.
CNBC reported that App Stories will bring Snap's content to more places, particularly to users who don’t currently use Snapchat.
The news service reported that Snap won't be making money from App Stories just yet, but it does give Snap more places to show ads.
Snapchat users can share their Stories to other platforms and communities to which they belong. They can also choose to share content to those other destinations but not with their friends on Snapchat.
Snap introduced Stories in 2013. Stories enables users to post full-screen photos and videos that disappear after 24 hours.
App Stories makes it easier for third-party software developers to bring Stories features onto their apps by simply using Snapchat’s existing technology.
This removes the need for software developers to build their own Stories features from scratch, the company said.
App developers can choose to keep Stories posts live for up to seven days, rather than the standard 24-hour limit.
Snap said it added more than 150 partner-app integrations via Snap Kit during the fourth quarter.