Snapchat first opened its API to a limited number of advertisers back in 2016, enabling third-party technology and creative companies to deliver ads on behalf of brands and agencies. It represented Snapchat’s first moves in the programmatic advertising realm, meaning that ads could be bought and sold automatically, and advertisers could experiment with different kinds of ads through A/B testing to see what works best. Or, for example, a retailer could optimize their ads based on their inventory — if stock runs low on one product, they could automatically switch ads to promote another product.
Source: Snapchat’s Marketing API is now available to all developers | VentureBeat