Zulip

Zulip is a free and open-source alternative to Slack, built for team communication. What makes Zulip unique is its threaded conversations, where each message belongs to a specific topic inside a channel. This helps teams stay organized, reduce noise, and easily follow multiple discussions at once. It’s great for remote teams, open-source projects, and companies that want focused, efficient communication.

Key features include:

• Threaded Conversations: Zulip's core feature, enabling focused discussions within channels.
• Powerful Search: Quickly find past conversations and information.
• Extensive Integrations: Integrates with a wide range of developer tools and services.
• Desktop and Mobile Apps: Available on all major platforms for seamless communication.
• API: Comprehensive API for custom integrations and automation.
• Self-Hosting Option: Offers both cloud-hosted and self-hosted deployment options for greater control and compliance.

Zulip is used by businesses, open-source projects, research groups, and educational institutions to streamline communication and collaboration. Its organized structure makes it particularly well-suited for remote teams and complex projects.