Telegram is a messaging app created by former VK creators with a focus on speed and security. It’s superfast, simple and free. It is like SMS, but more powerful.
- - Telegram is the most popular Web-based, Windows, Android & Mac alternative to SeaFour.club.
- - Telegram is the most popular free alternative to SeaFour.club.
Element is a secure collaboration and messaging app based on the Matrix protocol. It’s decentralised to deliver digital sovereignty, and based on an open standard for easy connections and interoperability. It is end-to-end encrypted by default.
- - Element is the most popular Self-Hosted alternative to SeaFour.club.
- - Element is the most popular Open Source alternative to SeaFour.club.
Pidgin is an easy to use, multi-protocol chat client client used by millions. Connect to AIM, MSN, Yahoo, XMPP, and more chat networks all at once. It has built-in support for NSS, offering client-to-server message encryption for protocols that support it.
Jitsi Desktop (previously SIP Communicator) is a legacy audio/video and chat communicator with full encryption, precedessor of Jitsi Meet .
Jitsi Desktop FeaturesDiscontinued
Jitsi Desktop is not actively developed anymore: last version, released in October 2017, can be still downloaded from GitHub. Its successor is Jitsi Meet
WhatsApp is an iPhone and Android messaging app which allows you to exchange messages without having to pay for SMS.
Zulip is the only modern team chat app that is designed for both live and asynchronous conversations. Zulip topics create a separate space for each discussion, so different conversations will never get in each other's way.
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].
Facebook Messenger is a faster way to message. Reach friends right on their phones, get and send messages fast, message everyone at once and more.
Facebook Messenger Features
Linphone is one of the most famous open source softphones in the world. It is fully SIP-based, for all calling, presence and IM features.
Trillian is an instant messaging app that works on phones, tablets, and desktops while keeping your chats neatly synchronized between all of them! We think conversation should be easily shared between all of your devices, not trapped as text messages on your phone.
- - Trillian is the most popular SaaS alternative to SeaFour.club.
Empathy is a messaging program which supports text, voice, video chat, and file transfers over many different protocols. You can tell it about your accounts on all those services and do all your chatting within one application.
Empathy is currently unmaintained. Last version, 3.25, released in August 2017, can be still downloaded from the official website.