UserVoice - UserVoice integrates easy-to-use feedback, helpdesk, and knowledge base management tools in one platform that empowers users to speak and companies to understand.

AppFollow - AppFollow is an integrated solution that makes monitoring, analyzing, and elevating your app's reputation easy.

Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community

AppSimilar - AppSimilar provides free service to analysis App Store Optimization (ASO), DAU, revenue & downloads, rating, reviews and so on. Various metrics help to improve your app performance, also can help keep up with your competitors’ app.

Zendesk - Zendesk is a beautiful, lightweight help-desk solution.

Userwish - Userwish is a SaaS web app that helps business owners build customer driven product roadmaps.