SiteGainer - SiteGainer is an A/B testing and conversion optimization platform.
Optimizely - A/B testing you'll actually use.
Splitly - Splitly is an A/B testing tool for Amazon FBA sellers.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
Chartbeat - Chartbeat shows you real-time traffic to your website and allows you to set alerts for any downtime or spikes in traffic.
invesp Pii Testing Engine - invesp Pii testing engine offers A/B testing solution for site optimization.