What is the difference between Flock and Zulip?

Flock is best for Teams wanting messaging with built-in productivity tools, while Zulip is best for Open-source communities and teams wanting threaded messaging. Flock starts at Free and Zulip starts at Free.

Is Flock or Zulip cheaper?

Flock starts at Free with a free tier. Zulip starts at Free and is free.

Is there a free alternative to Zulip?

Both Flock and Zulip offer free tiers.

Flock vs Zulip

Flock is team messaging with built-in to-dos, polls, notes, and file sharing, while Zulip is open-source team chat with a unique topic-based threading model for organized conversations. Zulip is open source and can be self-hosted, giving you full control over your data. Flock is built for teams wanting messaging with built-in productivity tools, whereas Zulip targets open-source communities and teams wanting threaded messaging.

At a glance

	Flock	Zulip
Best for	Teams wanting messaging with built-in productivity tools	Open-source communities and teams wanting threaded messaging
Starting price	Free	Free
Free tier	✓	✓
Open source	—	✓
Free tier available	✓	✓
Open source	—	✓
Markdown	—	✓
Notes	✓	—
Open Source	—	✓
Polls	✓	—
Self-Hosted	—	✓
To-Dos	✓	—
Topic Threading	—	✓
Video Calls	✓	—

Flock

Strengths

Lightweight to-do lists keep daily tasks front and center without project-management overhead
Includes Polls as a core feature, purpose-built for team communication workflows
Free for up to 20 users — generous enough for most small teams to get real work done
Established product with 12+ years on the market and a mature ecosystem

Weaknesses

Free plan exists but key features are locked behind the paid upgrade
Fewer built-in features means you may need additional tools to cover gaps
Notification overload is a real problem as the number of channels grows
Limited team/admin features if your organization eventually scales up

Try Flock → Full review

Zulip

Strengths

Open source and transparent
Topic-based threading keeps conversations organized by subject, not just time
Fully open-source — you can self-host, audit the code, and avoid vendor lock-in
The core product is free with no paywalled essentials

Weaknesses

May lack some advanced features
Self-hosting is free but requires server maintenance and DevOps knowledge
Self-hosting requires Linux admin skills and ongoing server maintenance
Notification overload is a real problem as the number of channels grows

Try Zulip → Full review

The bottom line

Pricing: Both Flock and Zulip are free. You can try both without spending a dollar.

Feature gaps: Flock offers Notes, Polls and To-Dos that Zulip lacks. Zulip brings Markdown, Open Source and Self-Hosted that Flock does not have.

Team fit: Flock is geared toward small teams teams, while Zulip is aimed at any size teams. Pick the one that matches where your team is today and where it is headed — migrating tools later is always painful.

Open source: Zulip is open source, meaning you can self-host, audit the code, and avoid vendor lock-in. Flock is proprietary — you are trusting the vendor with your data and uptime.

Where each tool shines: Flock's biggest strengths are: lightweight to-do lists keep daily tasks front and center without project-management overhead. includes polls as a core feature, purpose-built for team communication workflows. Zulip's biggest strengths are: open source and transparent. topic-based threading keeps conversations organized by subject, not just time.

Watch out for: With Flock, users commonly note that free plan exists but key features are locked behind the paid upgrade. With Zulip, the main complaint is that may lack some advanced features.

Choose Flock if...

Your profile matches its sweet spot: teams wanting messaging with built-in productivity tools
You specifically need Notes and Polls
You care about includes polls as a core feature, purpose-built for team communication workflows
Your team size fits the small teams profile Flock is designed for
The free tier works for you: free for up to 20 users

Choose Zulip if...

You need a tool built for open-source communities and teams wanting threaded messaging
You need self-hosting, data sovereignty, or the ability to audit source code
You specifically need Markdown and Open Source
You care about topic-based threading keeps conversations organized by subject, not just time
Your team size fits the any size profile Zulip is designed for