Optimizely - A/B testing you'll actually use.
xScope - xScope is an excellent utility that is used to measure the graphic layouts or any application’s dimensions for checking the operating systems’ compatibility with the desktop screen.
Dynamic Yield - Personalization & customer experience management
PixelSnap - Measure every pixel on your screen with ease ✨
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.
QuickLens - Inspect the UI of apps, illustrations & websites like a pro