What it actually is
Slack organises team communication into channels rather than threads in an inbox. Everything is searchable and public within a channel by default, which is a genuinely different model from email — new colleagues can read back and understand context instead of being forwarded into it.
What it’s genuinely good at
- Channels as shared context. The core idea still works: a project has a channel, and the history is there for whoever joins later.
- Search that people actually use. Finding a decision from four months ago takes seconds, which is not true of most communication tools.
- Integrations. Your monitoring, deployments, CRM updates and support tickets can all post into channels, turning Slack into a live dashboard of the business.
- Huddles and lightweight calls. Starting an audio huddle is faster than booking a meeting, and it quietly removes a lot of unnecessary calendar invites.
- Async-friendly culture. Teams that adopt it properly hold fewer meetings, because most questions can just be asked in a channel.
Where it falls short
Notification fatigue is real. Without deliberate channel hygiene, Slack becomes an interruption machine. Teams need naming conventions and norms about mentions, or people start muting everything — at which point the tool has failed.
Free plan limits history. The free tier restricts how far back messages are searchable and caps integrations. That single limit is usually what forces a growing team to pay.
It is expensive per seat for what it is. You are paying for chat, and at scale the bill adds up, particularly if most users are passive readers.
Knowledge does not live here. Decisions buried in channels are effectively lost. Anything that must be findable later belongs in a wiki or doc tool.
Who should use it
Remote or hybrid teams, and any team whose tools need to talk to each other. It is strongest where information flows continuously and where context matters more than formality.
Choose something else if: your organisation already pays for Microsoft 365 (Teams is bundled and “good enough”), you are a very small team that could use something simpler, or you need documentation more than conversation (Notion).
Pricing
A free tier supports small teams with limits on searchable history and app integrations. Paid plans start around $7 per user per month and add unlimited history, more integrations and admin controls. Because it is per seat, audit your actual active users before renewing — passive accounts are a common source of wasted spend.
Alternatives worth considering
- Microsoft Teams — bundled with Microsoft 365; choose it for cost and Office integration rather than quality.
- Discord — free, generous limits and excellent voice; genuinely viable for small teams and communities.
- Mattermost or self-hosted options — for organisations with data-residency requirements.
Our verdict: still the best team chat available, and still the tool that most changes how a distributed team works. Its success depends on discipline, not software: set channel conventions early, be sparing with mentions, and move decisions into documents where they can be found.
Frequently asked questions
Is Slack free?
Yes for small teams, but the free plan limits searchable message history and the number of app integrations. Growing teams usually hit the history limit first.
What is the 90-day history limit?
On the free plan you can only search back a limited window of messages. Older messages still exist but are not searchable, which is the main reason teams upgrade.
Slack or Microsoft Teams?
Teams if you already pay for Microsoft 365 and want everything in one place. Slack if chat quality, search and third-party integrations matter most.
How do teams stop Slack becoming overwhelming?
Naming conventions, a rule that not everything needs a channel, restrained use of @-mentions, and moving decisions into documents rather than leaving them in threads.