Pinterest forecast first-quarter revenue above market estimates on Thursday, betting on the image-sharing platform's artificial intelligence-powered advertising tools to boost ad spend, sending its shares up 22% in extended trading.

Pinterest Inc. posted strong holiday-quarter revenue and gave an upbeat forecast for sales in the current period, a sign that its advertising business continues to grow despite increased competition from much larger rivals in the social networking space.

The advertising business continues to grow despite increased competition from much larger rivals in the social networking space.