How to self-host your Slack alternative
With self-hosted team chat, your organization's message history lives on your server — no free-plan visible-message limit, no blocked export.
Tools that meet this intent
Alternative to Slack
Self-hostable team chat, an alternative to Slack.
Alternative to Slack, Microsoft Teams
Security-focused team chat and collaboration, an alt. to Slack.
Alternative to Linear, Notion, Slack
Projects + chat + docs in one, an alternative to Linear/Notion/Slack.
Alternative to Slack
Team chat organized by threads, an alternative to Slack.
Real server requirements
Between 512MB and 1GB of RAM depending on the tool — never a single number.
Real range across the 4 alternatives: from 512MB (Zulip, the lightest) to 1GB (Rocket.Chat, Mattermost, Huly). Mobile push notifications usually need your own Firebase/APNs project configured — they don't come ready out of the box like Slack's.
The real server requirement isn't fixed — it grows with how many people are connected at once, your message/history volume, the files you upload, and how many integrations/bots you run. Database and file storage are usually the first bottlenecks as a team grows, not CPU — and mobile push notifications (mentioned above) may need separate tuning as volume grows. We're not giving a "supports up to X users" figure per tool here: the catalog doesn't have that verified data, and a number without a real source would be a promise we can't back.
What you gain and lose versus the SaaS
You lose Slack's catalog of thousands of third-party integrations; you gain full control over how long history is retained and no message limit imposed by a paid plan.