Team messaging has settled into a three‑horse race: Slack, Microsoft Teams, and Google Chat. The question for most buyers is not whether the tools work — they all do — but whether the extra cost of Slack buys enough productivity to outweigh the “free” alternatives bundled with office suites. Slack’s acquisition by Salesforce in 2021 added CRM hooks, yet the core experience remains a channel‑first chat app with a massive app directory and a pricing model that penalizes the free tier heavily.

Free users hit a hard wall after 90 days: messages older than that vanish from search and scroll. For a product team that revisits design decisions or a support crew that audits tickets, that cliff is a deal‑breaker. The Pro tier removes the limit, adds unlimited integrations, and opens the door to Slack AI, a paid add‑on that can summarize threads and surface answers from the archive. Business+ and Enterprise Grid layer on compliance, SSO, and dedicated support, but the price jumps to $12.50 per user per month and custom contracts respectively.

Competitors have different leverage points. Teams ships with every Microsoft 365 seat, so the marginal cost is zero for existing customers. Google Chat rides along with Workspace. Discord, while not built for enterprise, has captured many engineering groups with its async‑first culture and zero‑cost model. Slack’s differentiator is the combination of a polished UI, the deepest integration catalog, and Slack Connect for cross‑company channels — features that still feel purpose‑built rather than bolted on.

Slack Free — 6.5/10

The free tier works for tiny, short‑lived projects: a startup validating a concept, a study group, or a side hustle that never needs to look back. You get unlimited channels, one‑to‑one DMs, and up to ten app integrations — enough for a basic Trello board or GitHub notifications. Huddles are included, so quick voice calls cost nothing extra.

The fatal flaw is the 90‑day message history. After three months, every conversation older than that disappears from search results and the scrollback buffer. There is no archive export for free workspaces, so institutional knowledge evaporates. Teams that survive past the pilot phase inevitably hit this wall and must upgrade or migrate.

Pricing reality: $0 per user, but the hidden cost is the time spent rebuilding context lost to the history cliff. For any team that expects to operate longer than a quarter, the free plan is a trap.

Slack Pro — 8.9/10

At $7.25 per user per month (billed annually) the Pro plan unlocks unlimited message history, unlimited app integrations, and the ability to purchase Slack AI. The AI add‑on costs extra but delivers thread recaps, channel summaries, and natural‑language search that can turn a noisy channel into a searchable knowledge base. For product and support teams that drown in chatter, that alone can shave hours off weekly triage.

Huddles remain a standout: one click starts a voice or video call with screen share, no calendar invite required. The latency is low enough for pair‑programming sessions, and the recording option lets absent members catch up later. Slack Connect lets you invite external vendors, clients, or partner teams into shared channels without guest accounts, preserving security policies on both sides.

The integration count — over 2,600 — means most SaaS tools already have a native Slack app. Custom workflows via Workflow Builder automate routine hand‑offs (e.g., posting a Jira ticket when a specific emoji reacts). The price is steep compared to Teams’ zero marginal cost, but the UI polish, search speed, and ecosystem depth still feel a generation ahead of the bundled competition.

Verdict

If your company runs on Microsoft 365, Teams is the rational default — you already own it, and the feature gap has narrowed enough that most users won’t notice. For organizations on Google Workspace or a mixed stack, Slack Pro delivers a superior day‑to‑day experience: faster search, richer integrations, and a cross‑company channel model that competitors have not replicated. The free tier is only viable for throwaway projects; any serious team should budget for Pro or higher.

Bottom line: Slack remains the best‑in‑class chat platform for teams that can afford it. The price premium is real, but so is the productivity gain from a tool that stays out of the way while connecting every other service you use.

Is Slack AI worth the extra cost?

Slack AI adds thread summaries, channel digests, and natural‑language search. For teams that generate hundreds of messages daily — support, engineering, sales — the time saved on manual triage often pays back the add‑on fee within a month. Small teams with low volume will see little benefit.

Can I migrate from Slack Free to Pro without losing data?

Upgrading restores the full message history from the moment you switch to Pro. Messages older than 90 days that were already purged on the free plan cannot be recovered, so plan the upgrade before the 90‑day window closes if you need that archive.

How does Slack Connect differ from guest accounts in Teams?

Slack Connect creates a shared channel that lives in both organizations’ workspaces, with each side controlling its own retention and compliance policies. Teams guest accounts add external users to your tenant, which can expose your directory and require more admin overhead.

What happens if I exceed the 10‑integration limit on the free plan?

You cannot add more apps until you remove an existing integration or upgrade to Pro. The limit applies to installed apps, not to the number of users or channels.