Just five months after its debut, Instagram Stories already boasts 150 million daily viewers, up from 100 million in October and on par with the last number announced by Snapchat. Now the company is looking to monetize that massive audience with 5-second photo and 15-second video ads.

The ads will appear between different people’s stories and can be easily skipped. Trials will begin with content from more than 30 companies — including General Motors, Netflix, Airbnb and Capital One — before expanding to all advertisers in coming weeks. As you would expect advertisers will be able to see the reach, impressions, and engagement for each Instagram Story.

Instagram started showing ads on users’ feeds in late 2013 when it had amassed around 150 million daily active users too. Currently the app as a whole has 600 million monthly and 300 million daily users. 

The Stories format is essentially a direct clone of Snapchat’s similarly named feature, which encourages users to share more spontaneous moments as photos and short videos that disappear after 24 hours. the 

Two services are going head-to-head when it comes to photo and video sharing as well as grabbing companies’ ad dollars. According to Instagram’s director of product marketing Jim Squires, the main advantage Instagram has over Snapchat is that it can offer advertisers precise targeting from Facebook, based on demographic and interest-based signals that have been built up over many years.