The Sightengine service scans incoming photos using an algorithm that includes shape recognition, machine learning, and database matching. It searches for female nipples, breasts, genitals, groin area, naked buttocks, and inappropriate objects, and flags them if the content exceeds PG standards. Their Nudity Detection API is a RESTful API. Requests are simply directed to their HTTP endpoints. Sightengine advertises that the algorithm clocks in at a 1% average false negative error on photos with adult content. To increase the chance of a photo not being flagged for nudity, one can delimit stricter parameters for increased control.