Zulip Alternatives for Mac OS X

Skype is a versatile communication platform offering free voice and video calls to other Skype users, as well as affordable calls to landlines and mobile phones worldwide. It provides instant messaging, file sharing, and screen sharing features, making it a comprehensive tool for personal and professional connectivity across various devices.

Telegram is a fast and secure cloud-based instant messaging platform offering robust privacy features, large group support, file sharing, and cross-platform synchronization, making it a versatile communication tool.

Slack is a leading cloud-based platform designed for team communication and collaboration. It offers a central location for conversations, file sharing, and app integrations, enabling teams to work more efficiently and stay connected regardless of location.

Tox is a free, open-source, and secure peer-to-peer instant messaging and video calling protocol designed for strong privacy and censorship resistance. It provides end-to-end encrypted communications without reliance on central servers.

Trillian is a versatile, multi-protocol instant messaging client that unifies various communication platforms like IRC, XMPP, and more into a single, user-friendly interface. It's designed for both personal and team collaboration, offering features like encrypted chats, group collaboration tools, and extensive customization options.

Viber is a comprehensive messaging and VoIP application enabling free and secure calls and messages to users worldwide. It offers robust features for both individual and group communication across various devices.

Signal is a secure, open-source messaging application that uses end-to-end encryption to protect user communications. It offers text messaging, voice and video calls, group chats, and file sharing, all with a strong focus on privacy and security. Available on multiple platforms, Signal is a leading choice for individuals prioritizing confidential conversations.

Glip, by RingCentral, is a comprehensive team collaboration platform combining real-time messaging, video calls, task management, and file sharing into a single, searchable hub. Designed to streamline communication and workflow, it aims to replace disjointed tools with a unified digital workspace.

LINE is a versatile communication platform offering free voice and video calls, messaging, and a wide array of interactive features to connect with friends and family globally. It goes beyond basic chat with unique stickers, timeline posts, and integration with various services, providing a comprehensive social and communication experience in one app.

Mattermost is an open-source, self-hosted platform for secure team collaboration, offering a Slack-alternative with emphasis on data control, privacy, and customizability. It provides a range of communication and project management tools for distributed and technical teams.

Wire is a secure, cross-platform messaging and collaboration client offering end-to-end encryption by default for all communication types including messaging, voice and video calls, and file sharing across desktop and mobile devices.

ICQ is a veteran instant messaging platform offering a wide range of communication features, including text chat, voice and video calls, screen sharing, and group chats. It aims to provide a reliable and feature-rich messaging experience with a focus on privacy and security.

Rocket.Chat is a comprehensive free and open-source team communication platform, offering real-time chat, audio/video conferencing, screen sharing, and file sharing. Designed for flexibility, it can be self-hosted on-premises for maximum control and customization, making it ideal for organizations prioritizing data privacy and security.

WeChat is a comprehensive mobile app offering instant messaging, social networking, payment services, and access to a wide range of mini-programs. It facilitates communication through text, voice, and video, supports group interactions, and integrates various lifestyle services.

Instantbird is a powerful, cross-platform instant messaging client built on Mozilla's XULRunner, leveraging the robust libpurple library from Pidgin. It supports a wide array of instant messaging protocols, offering a unified chat experience.

KakaoTalk is a popular mobile messaging service offering free text, voice, and video calls. Primarily used in South Korea, it provides a comprehensive communication platform with features like group chats, stickers, and a strong emphasis on user privacy and security.

Flock is a comprehensive communication and collaboration platform designed for teams. It streamlines workflow and enhances productivity through integrated messaging, project management tools, and seamless file sharing within a secure environment.

Zoiper is a versatile and easy-to-use SIP softphone designed for clear voice and video communications. It offers excellent audio quality, robust security features, and seamless integration with various communication protocols, making it ideal for personal and business use.

Tencent QQ (QQ) is a versatile instant messaging and social platform widely used in China and expandingglobally. It offers a wide range of communication tools including text chat, voice and video calls, group chats, and file sharing.

QuteCom, formerly WengoPhone, was a free and open-source VoIP client supporting the SIP protocol. It enabled users to make voice and video calls, send instant messages, and connect with contacts across various networks, including Google Talk.

Gitter is a free and open-source instant messaging and chat service designed specifically for developers and users of GitHub projects. It provides real-time communication within the context of software development teams and communities.

Wickr is a secure and private instant messaging platform designed for individuals and teams who prioritize confidentiality. It offers end-to-end encryption, self-destructing messages, and a focus on anonymity to ensure that conversations and shared data remain protected.

Dialog Messenger is a robust, feature-rich enterprise messaging solution designed for businesses prioritizing security, privacy, and control. Available for both private server deployment and cloud hosting, it facilitates secure text, voice, and video communication across multiple devices, enabling seamless collaboration and real-time interaction within organizations.

Tkabber is a free and open-source instant messaging client specifically designed for the XMPP protocol. Built with the Tk toolkit, it offers a lightweight yet extensible platform for text-based chat, group conversations, and various interactive functionalities supported by XMPP.

mySMS is a comprehensive cross-platform messaging solution that extends your smartphone's texting capabilities to your computer and tablet. It allows you to send and receive SMS messages from virtually any device, enhancing convenience and efficiency.

Toky is a comprehensive cloud-based phone system designed for businesses, offering voice calls, SMS, call recording, and integrations with various CRM and business tools. It provides teams with a flexible and powerful communication platform for customer support and internal collaboration.