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
Cloud-based team messaging platform with 750,000+ active workspaces
Open-source team chat with topic-based threading and self-hosting options
Pricing Model. Message Organization. Active Integrations Available. Hosting Options. Global Market Share. Message Search Speed. Free Trial Length
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.
Slack: Up to 2,000 (with paid plan) | Zulip: N/A
Slack: Limited (third-party connectors) | Zulip: N/A
Slack: Slack AI (summarization, search, assisted writing) | Zulip: N/A
Slack: Excellent - optimized search indexing | Zulip: N/A
Slack: $3,600 (Pro plan at $15/user) | Zulip: $140 (Cloud Standard flat-rate)
Slack: 7 days | Zulip: 14 days + unlimited self-hosted
Slack: 20+ million | Zulip: 0.15+ million
Slack: 10,000 most recent | Zulip: 100% unlimited
Slack: $8.25 (Pro plan, min 3 users) | Zulip: N/A
Slack: Unlimited (Slack Huddles for video limited to 50 participants) | Zulip: N/A
Slack: Huddles for brief video, limited to 50 participants; requires external tool for full conferencing | Zulip: N/A
Slack: Not native; requires integration with Otter.ai or similar third-party services | Zulip: N/A
Slack: 5 out of 5 (core feature with channels, threads, and history) | Zulip: N/A
Slack: 2 out of 5 (available via integration, not native) | Zulip: N/A
Slack: 30+ (CRM tools, meeting summaries, automation, SlackBot enhancements) | Zulip: N/A
Slack: Cloud-based SaaS only | Zulip: N/A
Slack: Compliant but data on Salesforce servers | Zulip: N/A
Slack: No increases for 33 months | Zulip: N/A
Slack: Unlimited group chats | Zulip: N/A
Slack: Workflow automation, search enhancement | Zulip: N/A
Slack: Optimized with threads and archives | Zulip: N/A
Slack: Slack AI (optional on paid plans) | Zulip: N/A
Slack: Limited (requires custom setup) | Zulip: N/A
Slack: Advanced with conditional logic | Zulip: N/A
Slack: Advanced AI assistant, smart summaries, automation | Zulip: N/A
Slack: $150 (billed monthly) | Zulip: N/A
Slack: 0 (not native feature) | Zulip: N/A
Slack: Unlimited (slide deck view only) | Zulip: N/A
Slack: DMs only, Enterprise+ plan | Zulip: N/A
Slack: Slack AI (search, summarization, drafting) | Zulip: N/A
Slack: $12.50 per user/month | Zulip: N/A
Slack: Advanced (Workflow Builder, automations) | Zulip: N/A
Slack: Unlimited external guests via workspace invite | Zulip: N/A
Slack: $8-12.50 (Pro/Business+) | Zulip: $0 self-hosted / $100-500 flat cloud
Slack: 10 years standard | Zulip: Unlimited (self-hosted)
Slack: Channel-based threads (contextual loss in active channels) | Zulip: Topic-based (complete conversation isolation within streams)
Slack: Proprietary (closed-source) | Zulip: Apache 2.0 open-source
Slack: Native iOS/Android with feature-parity | Zulip: Web-based with limited native apps
Slack: 50+ | Zulip: Custom via integrations (~15 standard)
Paid Workspaces/Users (Enterprise Adoption)
Slack: 750,000+ paid workspaces | Zulip: N/A
Slack: $150/month ($1,800/year) | Zulip: N/A
Slack: 90-day limited access | Zulip: N/A
Slack: 750,000+ active workspaces | Zulip: N/A
Slack: Yes (Business+ plan required) | Zulip: N/A
Slack: $12.50/user (Pro plan) | Zulip: N/A
Slack: 10,000 messages (free); unlimited (paid) | Zulip: N/A
Slack: No (requires integrations) | Zulip: N/A
Slack: 5GB (Free), varies by plan | Zulip: N/A
Slack: SOC 2, HIPAA, FedRAMP, GDPR | Zulip: N/A
Slack: 1 GB shared workspace | Zulip: N/A
Annual Subscription Cost (Pro, 100 users)
Maximum video call participants (free tier)
Slack: 2,000+ apps (Slack App Directory) | Zulip: N/A
Slack: Cost-effective until ~12 users | Zulip: N/A
Slack: No: messaging-only, requires integrations | Zulip: N/A
Slack: 90 days (Free/Pro), unlimited with Enterprise | Zulip: N/A
Slack: 750+ million messages daily across 750k+ organizations | Zulip: N/A
Monthly Subscription Cost (Pro/Standard)
Slack: All messages indexed instantly | Zulip: N/A
Maximum Video Conference Participants (Free)
Slack: Limited (typically 3-4) | Zulip: N/A
Slack: 4.6/5 (12,400 reviews) | Zulip: N/A
Slack: Full-text indexed across all messages | Zulip: N/A
Slack vs Zulip — Structured Comparison Data
Machine-readable comparison dataset for Slack vs Zulip. Contains 151 attribute comparisons, 5 FAQ pairs.
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.
Pricing Model: Slack has $8-15 per user/month (Pro-Business+), while Zulip has $100-300 per month flat-rate or self-hosted free.
Message Organization: Slack has Linear chronological chat with thread replies, while Zulip has Topic-based threading with stream organization.
Active Integrations Available: Slack has 2,400+ third-party integrations, while Zulip has 150+ integrations.
Hosting Options: Slack has Cloud-only SaaS, while Zulip has Cloud SaaS + self-hosted open-source.
Global Market Share: Slack has 65% of enterprise team chat market (2024), while Zulip has 2-3% of enterprise team chat market.
Message Search Speed: Slack has 2-4 seconds average search response, while Zulip has Sub-1 second due to threading indexing.
Free Trial Length: Slack has 7 days with limited history, while Zulip has 14-day free trial or unlimited self-hosted.