Zalo is described as '=> Message your friend in a snap. Receive notifications the moment they reply back' and is an app in the Social & Communications category. There are more than 25 alternatives to Zalo for a variety of platforms, including Android, iPhone, Windows, Android Tablet and Mac. The best alternative is Telegram, which is free. Other great apps like Zalo are Signal (Free, Open Source), Skype (Freemium), WhatsApp (Free) and Viber (Freemium).
Signal is a messaging app with an unexpected focus on privacy, combined with all the features expected from a modern IM app. Signal has received a lot of praise from all around the world for its security and privacy-respecting technologies.
Skype is the most popular free voice-over IP and instant messaging service globally. It allows users to text, video and voice call over the internet. Users can also call landlines and mobiles at competitive rates using Skype credit, premium accounts and subscriptions.
WhatsApp is an iPhone and Android messaging app which allows you to exchange messages without having to pay for SMS. In addition to basic messaging WhatsApp users can create groups, send each other unlimited images, video and audio media messages.
With Viber, everyone in the world can connect. Freely. More than 460 million Viber users text, make HD-quality phone and video calls, and send photo and video messages worldwide over WiFi or 3G - for free.
Conversations is a privacy focused, open source XMPP Texting [Jabber] client for Android 4.0+ smart phones with wife-approved easy encryption [OTR, OMEMO, or GPG]. [Note] **You can download the compiled apk for free from F-Droid**: ...
LINE is a Japanese proprietary application for instant messaging on smartphones and PCs. Line users exchange text messages, graphics, video and audio media, make free VoIP calls, and hold free audio or video conferences.
FluffyChat is an open, nonprofit and cute matrix messenger app for Ubuntu Touch, Android and iOS. Open Opensource and open development where everyone can join. Nonprofit FluffyChat is donation funded. Cute ? Cute design and many theme settings including a dark mode.