NEW YORK: Snapchat has taken a major step forward in its advertising business with the announcement of an advertising API, Snapchat Partners, that will enable ads to be sold by third parties.

But while API inventory will be sold via an automated, auction-based system, Snapchat will continue to inspect every ad in order to ensure quality, Adweek reported.

Peter Sellis, Snapchat's head of monetisation, also sought to reassure users on the volume of ads that would be appearing. "We have to be thoughtful about the inventory, ad load and the ad experience," he acknowledged.

"But we also know that we cannot build custom ad-tech solutions for every big type of advertiser, for every vertical," he continued.

"By doing this the right way, focused on creativity and doing it early, it allows us to be extraordinarily conservative," Sellis said, adding: "Something that I think often gets lost is that ad effectiveness can be inversely correlated with the number of ads that the viewer sees. If you see 50 ads in a day, the probability of you remembering them is low."

With swipe-up rates on current Snapchat ads reported to be five times higher than click-through rates on other social media, brands are expected to be very keen to get involved with the fast-growing platform that is popular with sought-after younger consumers.

So much so, Adweek suggested, that Snapchat could potentially attract adspend that marketers might otherwise "throw at mobile banners or lose to ad fraud" – as neither exists on the platform – and could even "steal away a chunk of millennial-focused brands' TV budgets".

Advertisers testing the new offering include Procter & Gamble, Universal Pictures, Paramount Pictures, Verizon, Warner Bros. and Express.

Snapchat was recently reported to have overtaken Twitter in terms of its number of daily users, having added 40m in six months to reach a total of 150m.

And eMarketer has predicted it will add twice as many new users as Twitter and Pinterest over the next four years.

"Different marketers have different objectives, and we just want to make it easier for them to buy ads on the platform," said Imran Khan, chief strategy officer at Snapchat.

"We want [brands] to have a place where they can tell their stories … in a better way," he added.

Data sourced from Ad Week, eMarketer; additional content by Warc staff