A free app for Android, by 9Softs Inc.
There are many alternatives to the official Facebook and Messenger apps. While the official apps are great, lightweight, and easy to use, there are a lot of problems with them. For one, you can’t customize the colors of your conversations on Facebook Messenger. Also, the official apps are based on the web, which means that your friends have to be on a Wi-Fi connection to be able to talk to you. If you’re on a mobile phone, this can be a problem. In the meantime, Mini Messenger for Facebook is a lightweight alternative that allows you to chat with your Facebook friends, send emoticons, videos, images, and gifts, browse your newsfeed, comments, etc., and protect your privacy.
It is free and is the best alternative for both Facebook and Messenger.