Going into 2016, Snap executives set a high bar for themselves in trying to pull in around $300 million in revenue—many times last year’s number. With the year nearly over, Snap has far exceeded that target, according to multiple people close to the company, and going into 2017 has again set an aggressive goal of $1 billion.

Next year they’ll have to do it under the glare of public scrutiny that will accompany its expected public offering. But it could be an uphill struggle, as some marketers have already balked at increasing their spending on Snap. They see the ad formats it offers as hard to use, say ad executives.