Naven
Answers
Is there a free alternative to Slack?
Yes. Discord, Google Chat (free with a Google account), Microsoft Teams (free plan), Zulip, and self-hosted open-source tools such as Mattermost, Rocket.Chat and Element all do most of what Slack's free plan does without its 90-day message history limit. Naven is a free, browser-based option for clubs, families and small groups rather than companies.
What people are escaping. Slack's free plan hides messages and files older than 90 days, limits integrations, and restricts huddles to two people. For a volunteer group or a club that is the history of everything it decided, gone after three months.
The realistic options.
Discord: free, generous, excellent voice channels, unlimited history. Built for gaming communities, and it shows: roles and permissions take learning, and it is not intended for under-13s.
Google Chat: free with any Google account, with spaces, threads, and integration with Drive, Calendar and Meet. Best if your group already lives in Google.
Microsoft Teams (free): chat, meetings and file sharing. Heavy, but familiar to anybody who uses it at work or school.
Zulip: open source with a free cloud tier for many communities; its topic-based threads suit groups that talk about many things at once.
Mattermost, Rocket.Chat, Element (Matrix): open source and self-hostable, closest to Slack, and completely free if you run the server yourself. That is the catch.
Naven: free, runs in a browser, needs only an email address, with group chats, channels, voice and video calls, a public forum, and Naven AI. It suits clubs, families, classes and small volunteer groups. It is not built for company compliance or integrations, and it is not end-to-end encrypted, because it screens messages before they are sent.
How to choose. If you need integrations with work tools, look at Teams or Google Chat. If you need a community with voice, look at Discord. If you need control of your data, self-host Mattermost or Element. If you need something a mixed group can open in a browser without installing anything, with everyone's age and safety taken seriously, try Naven.