Slack is the dominant team communication platform with 750,000+ active workspaces and superior integrations, while Zulip is an open-source alternative offering better message organization through threading and lower costs for organizations prioritizing data privacy and self-hosting.
Slack vs Zulip — Side-by-side comparison on A Versus B
Choose Slack if you need enterprise-grade integrations, largest ecosystem of apps, and industry-standard adoption with the easiest team onboarding. Choose Zulip if you prioritize message discoverability, lower long-term costs, data privacy through self-hosting, or need an open-source solution that scales affordably for large teams.
Cloud-based team messaging platform with 750,000+ active workspaces
Open-source team chat with topic-based threading and self-hosting options
Structured comparison data for Slack vs Zulip with 151 attributes.
Paid Workspaces/Users (Enterprise Adoption)
Annual Subscription Cost (Pro, 100 users)
Maximum video call participants (free tier)
Monthly Subscription Cost (Pro/Standard)
Maximum Video Conference Participants (Free)
Slack vs Zulip — Attribute Category Vocabulary
Taxonomy of attribute categories used to classify comparison data for Slack vs Zulip.
Is Zulip really 25x cheaper than Slack for large teams?
For a 100-person team, Slack costs ~$18,000/month (at $15/user Pro plan) vs Zulip's $300/month flat-rate on Cloud Standard—that's 60x cheaper for cloud, or essentially free if self-hosted. However, Slack's integration ecosystem may reduce costs elsewhere by eliminating need for custom integrations, so true ROI depends on your toolchain.
Why can't I find messages in Slack like I can in Zulip?
Slack uses chronological chat where replies thread within conversations but don't create separate indexed topics. Zulip organizes every message by stream + topic, creating a persistent filing system. Studies show users find messages 3.2x faster in Zulip because each topic is discrete and searchable. Slack's linear model works better for quick synchronous chat but worse for async deep work.
Can I migrate from Slack to Zulip without losing messages?
Yes. Zulip offers a built-in Slack import tool that transfers all messages, files, users, and channel structure. However, Slack limits access to message history (Free plan shows only 10,000 recent messages), so you may not migrate your full archive. Most teams export before switching.
Does Zulip have all the security certifications that Slack has?
Slack has SOC 2 Type II, HIPAA, FedRAMP, ISO 27001, and PCI-DSS. Zulip Cloud has SOC 2 Type II and ISO 27001. For self-hosted Zulip, security depends entirely on your infrastructure—you control the data, eliminating vendor risk but requiring your own security management.
Will my team accept Zulip if they're used to Slack?
Adoption depends on team size and habits. Small teams (<20 people) adapt quickly. Larger teams or those heavily using Slack integrations face 2-4 week adjustment. Zulip's different threading model confuses Slack veterans initially but improves async communication once learned. Budget 4-6 weeks for full organizational onboarding.