Quickblox has helped us build a robust community for our users. We are able to create new groups with ease as well as invite people from other platforms like Facebook messenger. The app can be very slow in some cases, but this is something we have been able to overcome with the help of their support team. I would recommend Quickblox to anyone looking for a cross platform messaging solution. We use Quickblox to create a community for employees at a client's company. It helps solve problems like scheduling in-person meetings and getting information out quickly to our entire workforce. The best thing about quickblox is its ease of use as well as all the features it provides. I have been using it for my project and it has helped me in many ways. It's free and can be used by anyone with an android device or ios devices. There are some other paid services but this one is free. So, if you're looking for something that is easy to use, try out quickblox. I am solving problems related to user engagement and retention.