Macgyver hosts the largest library of machine learning algorithm programs. Macgyver allows developers to incorporate state-of-the-art deep learning algorithms into their application with relative ease. Common tasks such as computer vision based facial recognition, nudity detection, natural language understanding are just a few of the programs we offer for developers to leverage.
FaceRect is a powerful and free API for face detection. It finds faces (both frontal and profile) on the image specified by URL or uploaded as a file and is able to find multiple faces on a single photo, producing JSON output with a bounding box for each face found. Check out visual demo here: http://apicloud.me/apis/facerect/demo/. Note that additionally FaceRect can find face features for each detected face (eyes, nose and mouth). For more precise face feature detection please see our FaceMark API: https://www.mashape.com/apicloud/facemark