Algolia - Algolia's Search API makes it easy to deliver a great search experience in your apps & websites. Algolia Search provides hosted full-text, numerical, faceted and geolocalized search.
Optimizely - A/B testing you'll actually use.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
Dynamic Yield - Personalization & customer experience management
Google Analytics - Improve your website to increase conversions, improve the user experience, and make more money using Google Analytics. Measure, understand and quantify engagement on your site with customized and in-depth reports.
MooSend - Moosend allows you to design and send your email marketing campaigns and track the results from an easy-to-use web interface as well as a direct SMTP server connection for your smtp client or web application.