Slack

Free Tier Ratings

Last Reviewed: 2026-07-14

Good for team coordination on marketing. 90-day history limit loses context.

Coordinate grant teams. 90-day limit problematic for multi-year grants.

Internal coordination only. External comms need email/CRM.

90-day limit loses institutional knowledge. Not for documentation storage.

90-day limit inappropriate for board communications that need retention.

Coordinate training. 90-day limit loses training materials context.

Team coordination for social. 10 integration limit constrains tools.

Coordinate campaigns internally. 10 integration limit may block email tools.

90-day limit loses research context. Not for research storage.

Team coordination. 90-day limit loses policy discussion history.

Event coordination works. History limit problematic for annual events.

90-day limit inappropriate for financial records needing retention.

Non-Generative ML Only

Does NOT train LLMs on customer data. Non-generative ML (emoji suggestions, channel recommendations, search) uses de-identified usage patterns — NOT message content. April 2025 clarification: ML models do not look at DM or channel message content.

Yes — Admin request

Org/Workspace Owner emails [email protected] with subject 'Slack Global model opt-out request' and workspace URL. Slack processes request and confirms. Generative AI never trains on customer data regardless of opt-out status.

Never

Slack AI stays within platform trust boundary. Customer data does not leave Slack's infrastructure. Third-party LLM providers have no access to customer data. No external training or human review.

90-Day Limit

Messages deleted after 90 days. Major limitation for institutional knowledge. Upgrade to Pro (FREE for nonprofits ≤250 members) for unlimited history.

SOC 2, ISO 27001/27017/27018/27701/42001

TLS 1.2+ in transit. AES-256 at rest. ISO 42001 (AI management system) certified. ISO 27701 (Privacy Information Management) certified. Strong baseline security across all plans. AI exclusion controls (Feb 2026) let admins mark channels off-limits for AI processing.

Exceptional Nonprofit Discount

Pro plan free for nonprofits with ≤250 members. 85% off all paid plans for larger organizations. Apply at slack.com/help/articles/204368833. TechSoup verifies eligibility. Churches, hospitals, schools, and government organizations do not qualify.

85% Education Discount

85% off Pro, Business+, and Enterprise Grid for educational institutions. Apply separately through Slack for Education program.

90-Day History Limit on Free

Free plan deletes messages after 90 days. This is a major limitation for institutional knowledge. Upgrade to Pro (FREE for nonprofits ≤250) for unlimited history.

3-User Minimum on Paid Plans

Even with 2 users, you pay for 3 on Pro and Business+. Minimum $21.75/month on Pro at full price.

Major Plan Transition Underway (2026-2027)

Slack announced March 3, 2026 that Enterprise Grid, legacy Business+, Enterprise Select, legacy GovSlack, the Slack AI add-on, and the Sales Elevate add-on will all retire on March 1, 2027, replaced by the new Business+ (v2) and Enterprise+ plans. Existing customers can keep using legacy plans until their next renewal after that date, but should discuss migration paths with their account team well in advance. This does not eliminate nonprofit discount eligibility, but the underlying plan names/features nonprofits are discounted on will shift.

Enterprise Grid Lock-In (Retiring 2027)

WARNING: Once you upgrade to Enterprise Grid, you CANNOT downgrade. Ever. This plan is also being retired March 1, 2027 in favor of Enterprise+ — new Enterprise Grid purchases should be avoided in favor of evaluating Enterprise+ directly.

No LLM Training on Customer Data

Slack does not train large language models (generative AI) on customer data. AI features use off-the-shelf LLMs via RAG — models don't retain customer data after requests. Non-generative ML (emoji/channel/search recommendations) uses de-identified usage patterns, NOT message content per April 2025 clarification. Opt out by emailing [email protected] with subject 'Slack Global model opt-out request.' New AI exclusion controls (Feb 2026) let admins mark specific channels/content off-limits for AI processing entirely.

AI Features Now Bundled and Expanding to All Tiers

Slack AI add-on discontinued August 2025 (and is being formally retired March 2027). Basic AI (conversation summaries, huddle notes) included in Pro. Advanced AI (recaps, translations, file summaries, workflow automation) included in Business+ and Enterprise+. Slackbot (personal AI agent) reached GA January 13, 2026 for Business+ and Enterprise+, and began rolling out to Free and Pro tiers in April 2026 — meaning Slackbot access is trending toward all tiers over time. Enterprise search across third-party apps (Google Drive, Salesforce, GitHub, etc.) remains Enterprise+ only.

Strong Security Certifications

SOC 2 Type II, SOC 3, ISO 27001/27017/27018/27701/42001, CSA STAR, Global CBPR/PRP on all plans; also FINRA 17a-4, FERPA, TISAX, IRAP, ISMAP, C5 (Germany), K-FSI (South Korea), and ENS High (Spain) for applicable customers. ISO 42001 (AI management system) and ISO 27701 (privacy) are relatively new certifications (2025). New in 2026: DLP secret scanning (Enterprise+/Grid, detects leaked API keys/credentials) and a 2-year audit log auto-deletion policy (effective April 30, 2026) that regulated organizations must plan around. HIPAA BAA available for Enterprise Grid and Enterprise+. FedRAMP Moderate authorized for standard Slack; GovSlack (separate instance) FedRAMP JAB High + DoD IL4 authorized (Dec 2025). NOTE: starting August 19, 2026, Slack customer support case data moves outside the FedRAMP boundary — organizations needing support data within that boundary must request an exception.

Common Sense Media: WARNING Rating

Common Sense Media rates Slack with a WARNING (not a pass) due to personalized advertising, data profiles created for ads, and user data used to target ads on third-party websites. This applies to the general Slack platform. Enterprise customers can negotiate stricter data handling terms. Rating unchanged as of mid-2026.

2026-07

Slack announced (effective August 19, 2026) that customer SUPPORT CASE data — not workspace data — is moving to Salesforce's commercial support infrastructure outside the FedRAMP-authorized boundary. Organizations requiring support data to remain within a FedRAMP boundary must submit a request before August 19, 2026. Relevant primarily to FedRAMP-obligated government and GovSlack customers.

2026-04-30

Two-year audit log retention policy took effect. Slack now automatically deletes audit logs older than 2 years across plans. Organizations in regulated industries (SEC requires 5-7 years, HIPAA requires 6 years, DFARS requires 7 years) must export and archive audit logs externally to meet longer compliance retention requirements.

2026-04

Slackbot (Slack's personal AI agent), previously GA only on Business+ and Enterprise+, began rolling out to Free and Pro tiers — expanding AI agent access to all Slack plans over time.

2026-03

Slack announced the retirement of several legacy plans and add-ons — Enterprise Grid, legacy Business+, Enterprise Select, legacy GovSlack, the Slack AI add-on, and the Sales Elevate add-on — all retiring March 1, 2027. These are being replaced by the new Business+ (v2) and Enterprise+ plans. Also introduced DLP secret scanning (Enterprise+/Grid) which automatically detects and removes leaked credentials (API keys, AWS keys, database connection strings, OAuth tokens, private keys) shared in messages, and a native Slack MCP server enabling external AI agents to securely connect to workspace data under existing permissions.

2026-03

New Slack AI features rolled out starting March 25-31, 2026: message explanations, canvas content generation, AI workflow automation, expanded Slackbot capabilities, and daily channel recaps for Business+ and Enterprise+ users. Full suite completed rollout by June 2026, including 30+ new Slackbot/agentic capabilities, deep Claude integration, and MCP client support for connecting to external tools (Google Docs, Linear, DocuSign, etc.) from within Slack.

2026-02

AI exclusion controls launched, letting admins designate specific channels and content as off-limits for AI processing — an added privacy/control lever for organizations wary of AI accessing sensitive conversations.

2026-01-13

Slackbot — Slack's personal AI agent — reached general availability for Business+ and Enterprise+ customers. Slackbot understands conversations, files, channels, and respects all existing permissions. Connects Slack data with Salesforce CRM data.

2025-12-09

GovSlack (government-specific Slack instance) achieved DoD Impact Level 4 (IL4) compliance authorization, adding to its existing FedRAMP JAB High status. Relevant only for defense/government nonprofits.

2025-08

Customers with Slack AI add-on transitioned to new plan versions at first renewal after August 17, 2025. Pro users lost advanced AI features unless upgrading to Business+.

2025-06

Major pricing/packaging update. Business+ increased to $15/user/month annual (from ~$12.50); monthly price later listed at $18/user. New Enterprise+ plan introduced. AI features bundled into tiers. Slack AI add-on discontinued. Pro now includes basic AI. Business+ and Enterprise+ include full advanced AI suite.

For organizations with 5+ staff

Pro is FREE for nonprofits ≤250 members — includes unlimited history and basic AI (conversation summaries, huddle notes), with Slackbot access rolling out from April 2026. Apply at slack.com/help/articles/204368833. Larger orgs get 85% off. For advanced AI and compliance controls (recaps, translations, compliance exports), Business+ at 85% off = ~$2.25/user/month is the sweet spot.

For organizations with fewer than 5 staff

Pro is FREE for nonprofits ≤250 members. Note 3-user minimum billing on paid plans for non-discount orgs. Free tier's 90-day limit is a major limitation — apply for nonprofit discount immediately if eligible.

For health data or vulnerable populations

Business+ (~$2.25/user with 85% discount) for SSO, compliance exports, and advanced security. Enterprise Grid required for HIPAA BAA and Enterprise Key Management — but note Enterprise Grid is retiring March 1, 2027 in favor of Enterprise+, so organizations should plan that transition now rather than newly purchasing Grid. Also be aware Slack's audit logs auto-delete after 2 years as of April 30, 2026; organizations with longer legal/compliance retention obligations (HIPAA 6 years, SEC 5-7 years) must export logs externally. Do NOT store PHI or sensitive client data on Free, Pro, or Business+ tiers — only Enterprise Grid/Enterprise+ with an executed BAA qualifies.