Comparisons
Fluid Chat versus everyone else.
Four head-to-heads, written the way you'd want a friend to write them — including the cases where the other tool is the right answer. Because a comparison page where the author wins every row is not a comparison page.
Architecture and pricing models, not feature-count theatre.
Fluid vs Mattermost
Both run on Postgres. Mattermost has the enterprise track record and the paid tiers to match; Fluid has no tiers at all.
Pick Mattermost for compliance-heavy enterprise rollouts.
JavaScript · MongoDBFluid vs Rocket.Chat
Rocket.Chat bundles voice, video and omnichannel into one deployment. Fluid does messaging only, on a much smaller ops surface.
Pick Rocket.Chat if you need calls and customer channels in the same box.
Python · PostgresFluid vs Zulip
Zulip's topic model is the best threading in the category — and the biggest habit change. Fluid keeps the channel model your team already knows.
Pick Zulip if your team genuinely thinks in topics.
The incumbentFluid vs Slack
The 90-day history limit, per-seat billing, and the admin features behind higher tiers — measured against a free product with none of them.
Pick Slack for huddles, Slack Connect and the app directory.
The whole field
Five tools, nine rows that matter.
Notice that Fluid loses three of these outright. That is what an honest table looks like.
| Fluid Chat | Mattermost | Rocket.Chat | Zulip | Slack | |
|---|---|---|---|---|---|
| Open source | Yes | Yes | Yes | Yes | No |
| Self-hostable | Yes | Yes | Yes | Yes | No |
| Database | Postgres | Postgres / MySQL | MongoDB | Postgres | — |
| Unlimited history free | Yes | Self-hosted | Self-hosted | Self-hosted | No (~90 days) |
| Per-seat pricing | None | Paid tiers | Paid tiers | Cloud tiers | Yes |
| Admin features gated | None | Some | Some | Some | Yes |
| Voice / video | No | Yes | Yes | Integrations | Yes |
| Native mobile apps | No | Yes | Yes | Yes | Yes |
| SSO / SAML | No | Paid | Paid | Paid | Paid |
Competitor details are summarised from each project’s public documentation and pricing pages and can change — check the source before making a decision on ours. Slack is a trademark of Salesforce; Mattermost, Rocket.Chat and Zulip are trademarks of their respective owners. Fluid Chat is an independent project and is not affiliated with any of them.
Comparisons are easier when nothing is hidden.
Every feature Fluid has is in the free product, and every feature it lacks is listed on these pages. Start a workspace and check.