Dialog Messenger Alternatives for Web

Jitsi is an open-source project and software toolset that allows you to easily build and deploy secure video conferencing solutions. At the heart of Jitsi are Jitsi Videobridge and Jitsi Meet, which let you have conferences on the internet, while other projects in the community enable other features such as audio, dial-in, recording, and simulcasting.  Jitsi supports popular protocols such as SIP, XMPP/Jabber, ICQ/AIM, Windows Live, Yahoo!, Google Hangouts, OTR, ZRTP and more.

Slack is a new way to communicate with your team in a faster, better organized, and more secure than email. The software is designed for business looking to improve their communication work flow. Slack offers features like persistent chat rooms organized by topic, private groups, and direct messaging that is built for teamwork.

WhatsApp is free messenger app for chat and voice over IP, owned and managed by Facebook. The application allow users to send text and voice messages, make voice and video calls and share images, media files and user locations with friends and family.

Mattermost is an open-source, self-hostable enterprise team collaboration and messaging application. The software can be deployed to on-premis or to cloud instances. Mattermost is designed for internal use within organizations and businesses in financial services, government, healthcare, remote work, and enterprise DevOps, where teams use Mattermost to power collaboration at every stage of the DevOps lifecycle.

A free, unlimited and open-source chat software. Rocket.Chat have set out to be a replacement for email, HipChat & Slack and is provided as Software-as-a-Service (SaaS) or a self-hosted community edition. Rocket.Chat is feature packed and can be used for video conferencing, file sharing, voice messages and more. The software integrates with third-party services like GitHub, GitLab, JIRA, and Confluence and provides an API that can be used for authentication and integration across these services.

Work anytime, anywhere with Asana. Keep remote and distributed teams, and your entire organization, focused on their goals, projects, and tasks. From the small stuff to the big picture, Asana organizes work so teams are clear what to do, why it matters, and how to get it done.

Zulip is an open-source real-time chat with an email threading model. With Zulip, you can catch up on important conversations while ignoring irrelevant ones. Zulip provides modern apps for every major platform, powered by Electron and React Native. The software is 100% open source software, built by a vibrant community of hundreds of developers from all around the world.

Gitter is an open-source instant messaging and chat room system for developers designed to make community messaging, collaboration and discovery as smooth and simple as possible. Gitter is provided as software-as-a-service and integrates with GitLab and GitHub repositories to make discussion around code even easier. With Gitter, you can can easily create, organise and grow your communities, inviting others to join just in one click. Over 1.5M users across 100K communities use Gitter to discuss code and development progress.