Pumble

Message history — that's the whole pitch. Pumble's free plan gives unlimited users and unlimited history, so conversations from months or years ago stay searchable. Slack's free plan cuts off at 90 days, meaning teams on long projects lose access to their own past discussions. Pumble free also covers channels, DMs, threads and file sharing. If permanent access to your team's knowledge matters, that gap is significant.

The real-time collaboration features. Audio calls, video conferencing, screen sharing and meeting recording are all paid-only, so free is effectively messaging and file sharing. Free storage is limited too, which reviewers mention regularly. Communicating mainly in writing? Free is genuinely sufficient. Need to jump on calls or share screens? Budget for Pro from the start.

Each active and invited user on a paid plan needs a paid seat — the "invited" part catches people out, since someone sent an invitation they haven't accepted still consumes a seat. The upside: deactivating a user frees their seat immediately for reassignment. Budget on everyone you'll invite, not just active users, and tidy up dormant accounts periodically.

On cost and data retention Pumble wins clearly — free keeps your full history where Slack stops at 90 days, and paid tiers start at a fraction of Slack's entry price. Slack has the larger app ecosystem, deeper integrations and broader enterprise adoption, which matters if your workflows depend on connected tools. Migration from Slack is straightforward and works even onto Pumble's free plan, so testing the switch costs nothing but time.

Best within its own family. Pumble is built by CAKE.com alongside Clockify (time tracking) and Plaky (project management), and the three integrate natively — they're also sold bundled in the CAKE.com Suite. Beyond that, the ecosystem is smaller than Slack's or Teams', though API access exists for custom connections. Already using Clockify or Plaky? Pumble slots in neatly. Stack built on many third-party apps? Check compatibility first.