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.

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.

Optimizely - A/B testing you'll actually use.

Dynamic Yield - Personalization & customer experience management

Smartlook - Qualitative analytics for websites and mobile apps Start understanding the 'whys' of your users' behaviors with clear, visual insights. With session recordings and event tracking, you get the complete picture.

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.