Depict.ai - Amazon-quality product recommendations for any online store
Recombee - Recommender system as a service that uses advanced Machine Learning and Artificial Intelligence algorithms. Easy to try and evaluate.
MailChimp Product Recommendations - Easily build automated personalized email marketing
Wylei - Wylei, a pioneer in Predictive AI cloud-based machine learning and marketing automation, creates & delivers real-time, personalized content.
Suto - Get one-on-one expert product recommendations.
Optimizely - A/B testing you'll actually use.