Slack is a team messaging platform from Salesforce, which acquired it in 2021. Teams organise work in channels, call in huddles, and message clients and vendors outside their own organisation. The vendor's pricing page lists a free plan and three paid plans. All prices below are in US dollars.
What agencies use Slack for
Slack gives an agency one place for internal conversation, client communication and routine automation. The vendor does not publish a page of agency uses, so the examples below come from its documented features.
Channels are the core unit. The vendor describes them as spaces for working with your team, AI assistants and agents. An agency might set one channel per client or per project, though Slack does not prescribe a structure.
Slack Connect lets you message clients and vendors in real time from Slack rather than email. On the Free plan it covers 1:1 direct messages with people outside your organisation. Paid plans add group chats and dedicated channels with up to 250 organisations.
Huddles are the built-in audio and video calls, with screen sharing. The vendor says AI in Slack can write meeting notes from them.
Workflow Builder handles recurring tasks such as stand-up prompts, project updates and approvals. Slack says anyone can build these by click or by code.
Over 2,600 apps are listed in the Slack App Directory, including Salesforce, Jira, Google Drive and ChatGPT. The Free plan allows up to 10 apps.
Plans and pricing
Slack has four plans: Free, Pro, Business+ and Enterprise+. Prices are per user per month, and the annual rate is lower than the monthly one.
| Plan | Billed annually | Billed monthly |
|---|---|---|
| Free | $0 | $0 |
| Pro | $7.25 | $8.75 |
| Business+ | $15 | $18 |
| Enterprise+ | $45 | Contact sales |
The vendor's page also shows a 50% discount for 3 months on Pro and Business+, marked with an asterisk. Check the vendor's pricing page for the terms of that offer.
What changes between plans:
- Free: 90 days of message history, up to 10 apps, 1:1 meetings and 1:1 external messages.
- Pro: unlimited message history and apps, group meetings, group external messages, AI conversation summaries.
- Business+: adds the vendor's advanced AI (Slackbot, workflow generation, AI search, daily recaps, file summaries), SAML single sign-on and SCIM user management.
- Enterprise+: the vendor's most comprehensive plan, sold through its sales team.
The vendor shows no free trial. The Free plan has no stated time limit.
Limits to know before you buy
Slack's Free plan keeps messages searchable for 90 days only. Older messages beyond that, up to the previous 12 months, are available only after upgrading. An agency that needs to find a client decision from last spring should plan for a paid plan.
Group conversations with clients need a paid plan. On Free, external contact is limited to one-to-one messages, so a shared client channel is not available.
Cost scales with headcount. Everyone who needs access, including freelancers who join your workspace, is a seat, so check how your team counts before comparing annual totals. Slack Connect lets you work with clients and vendors from their own Slack organization, but check Slack's own documentation on how seats are counted for your set-up.
Several AI features, including Slackbot, AI search and daily recaps, are not in Free or Pro on the vendor's comparison. Slackbot is also subject to plan limits.
If you are still choosing an agency rather than a tool, you can post your brief free.
Plans and prices as published on the vendor's own pricing page on 4 November 2026; check there before you buy. This is not a paid listing and Online Agency Network is not affiliated with the vendor.
