Optimizely A/B Testing - Optimizely A/B Testing is an experimenting platform that uses two or more versions of demographics to the users.
AbTest.io - A free url shortener with A/B testing features
Leanplum A/B Testing - Leanplum A/B Testing is a service that helps you maximize ROI by improving customer’s experience and building loyalty with the brand.
PreFlight - Preflight is an Automated Web Testing tool. Allows everyone to automate Web UI tests.
GoodUI Fastforward - Lift your conversion rate with repeatedly AB tested patterns
GoodUI Evidence - People's A/B test results that show which UI ideas work best