Compared to the number of ads that are submitted daily by over 2.5 million marketers, the Facebook ad staff is pretty small. While Facebook doesn’t openly discuss how the ad review process works, it is largely believed that an automated system that uses machine learning (AI) handles the first round of approvals.
If your ad doesn’t hit any red flags by the automated review, it will likely be approved within minutes. If it triggers a manual review (by a human), then it could take hours or even days around peak ad dates like holidays.
The automated process is most likely looking for the standard requirements like length, image or video quality, and aspect ratios. It is also scanning for prohibited or regulated material. The automated review can scan text, images, video, and audio. Some industries require more stringent reviews, such as dating sites, alcohol ads, and financial advice.