Userbrain - Easy, fast, and affordable user testing for websites and prototypes.
UserTesting.com - Usability testing has never been easier. Get videos of real people speaking their thoughts as they use websites, mobile apps, prototypes and more!
Instabug - The top apps in the world rely on Instabug for beta testing, user engagement and crash reporting.
AppKat - Recruit, track, schedule, manage and conduct usability tests, all in one simple, affordable...
UserTest.io - User testing made simple. High-quality, affordable user testing solutions from real users, here in the UK. Improve your usability!
Validately - Validately is a user feedback platform to test demand and usability on a clickable prototype or live feature.