# Slack

Slack (by Salesforce) is team-messaging software rated 4.5/5 on G2 (39,074 reviews) and 4.7/5 on Capterra. Profile: ownership, pricing, news.

**Category:** team messaging / collaboration platform  
**Vendor:** Slack Technologies, LLC (a Salesforce company)  
**Founded:** 2013 (product launch); parent Tiny Speck founded 2009  
**HQ:** San Francisco, California, US (Salesforce Tower, 415 Mission St)  
**Website:** https://slack.com/  


## About

Slack is a channel-based team-messaging and collaboration platform. It started inside Tiny Speck, the studio Stewart Butterfield founded in 2009 to build the game Glitch, and launched publicly as a standalone product in August 2013 after the game was shut down. Co-founded by Butterfield with Cal Henderson, Eric Costello, and Serguei Mourachov, it grew fast, went public via a direct listing on the New York Stock Exchange (ticker WORK) in June 2019 at a roughly $19.5 billion opening market value, and was acquired by Salesforce in a cash-and-stock deal valued at about $27.7 billion that closed in July 2021. Slack now operates as a Salesforce business unit, deeply tied into the Salesforce Customer 360, and is one of the most widely deployed workplace collaboration tools in the enterprise.

## Ratings

| Source | Score | Reviews |
|---|---|---|
| G2 | 4.5/5 | 39,074 |
| Capterra | 4.7/5 | 24,116 |
| Gartner Peer Insights | 4.6/5 | 7,502 |

## Funding

~$1.4B venture funding before its 2019 direct listing; acquired by Salesforce for ~$27.7B (2021)

| Round | Amount | Date | Lead |
|---|---|---|---|
| Series A (Tiny Speck) | $5M | 2010 | Accel, Andreessen Horowitz |
| Series D | $120M | Oct 2014 | Kleiner Perkins, GV (Google Ventures); $1.2B valuation |
| Series E | $160M | Apr 2015 | Horizons Ventures, Index Ventures; ~$2.8B valuation |
| Series F | $200M | Apr 2016 | Thrive Capital, Comcast Ventures; ~$3.8B valuation |
| Series G | $250M | Sep 2017 | SoftBank Vision Fund (with Accel); $5.1B valuation |
| Series H | $427M | Aug 2018 | Dragoneer, General Atlantic; $7.1B valuation |
| Direct listing (IPO) | NYSE: WORK | Jun 2019 | ~$19.5B opening market value |
| Acquisition | ~$27.7B | Jul 2021 (closed) | Salesforce (cash + stock) |

## Viability

Very low risk on solvency. Slack is a wholly owned business unit of Salesforce (NYSE: CRM), a profitable public company with 83,334 employees as of January 2026, so there is no funding-runway question. Salesforce paid about $27.7 billion for Slack in 2021 and has woven it into its Customer 360 platform and its agentic-AI strategy, which signals long-term commitment rather than wind-down. The real watch-items are different from a startup's: leadership has turned over (Stewart Butterfield left in 2022, Denise Dresser departed for OpenAI in December 2025, and Rob Seaman is interim CEO as of 2026), and Microsoft Teams' bundling into Microsoft 365 keeps competitive pressure high at the low end. For most buyers the practical risks are pricing creep and product-roadmap drift under a large parent, not the platform going away.

## Pricing

Slack's free tier is usable but capped at 90 days of searchable message history and 10 app integrations, which is the wall most growing teams hit. Paid pricing is per active user and stacks quickly: Pro is $7.25/user/mo annually (or $8.75 monthly), Business+ is $12.50/user/mo annually (or $15 monthly), and Enterprise+ (formerly Enterprise Grid) is custom-quoted, typically landing in the low-to-high-$20s per user in real deals. Slack AI, the search and summary layer, is bundled into paid plans now rather than sold as a separate add-on. Re-check the live per-user numbers before budgeting, since they shifted in the last year.

| Plan | Price | Best for |
|---|---|---|
| Free | $0 | Small teams; 90-day message history, up to 10 integrations, 1:1 huddles |
| Pro | $7.25/user/mo annual ($8.75 monthly) | Growing teams needing full message history, unlimited integrations, group huddles |
| Business+ | $12.50/user/mo annual ($15 monthly) | Larger orgs needing SSO/SAML, compliance exports, 24/7 support, advanced admin |
| Enterprise+ | Custom | 500+ users; multi-workspace governance, DLP, eDiscovery, FedRAMP Moderate |

## What reviewers say

_39,074 G2 reviews at 4.5/5 and 24,116 Capterra reviews at 4.7/5, plus 7,502 Gartner Peer Insights ratings at 4.6/5_

**Praised:**
- Channel-based organization plus fast, reliable search is the most-cited strength: teams keep conversations, files, and decisions in one searchable place instead of scattered email threads
- The integration ecosystem is the real moat; most major SaaS tools ship a quality Slack app first, and reviewers lean heavily on Google Workspace, Zoom, Jira, and Salesforce connections
- Low-friction onboarding and a clean interface, even non-technical team members adapt quickly, and huddles replace a lot of short meetings

**Complaints:**
- Notification overload is the single most-cited complaint, busy workspaces flood users with pings, and most teams need weeks of channel-hygiene work to calm it down
- The desktop app can feel heavy on system memory, especially with multiple workspaces, huddles, and integrations running at once
- Cost scales fast per seat, and the free tier's 90-day message-history cap pushes growing teams onto paid plans sooner than they expect

## Compliance

- **SOC 2:** Yes (SOC 2 Type II, also SOC 3)
- **GDPR:** Yes
- **HIPAA:** Yes (configurable; supports e-PHI on eligible plans)
- **SSO:** Yes (SSO / SAML; SCIM on higher tiers)

## Integrations

- Salesforce
- Google Workspace
- Microsoft 365 / Outlook
- Google Drive
- Zoom
- Jira
- GitHub
- Asana
- Zapier
- Notion

## FAQs

### Who owns Slack?

Salesforce, Inc. (NYSE: CRM). Salesforce acquired Slack in a cash-and-stock deal valued at about $27.7 billion, announced in December 2020 and closed in July 2021. Slack now operates as a Salesforce business unit and is integrated into the Salesforce Customer 360 platform.

### Is Slack free?

Yes, Slack has a free plan. It includes channels, direct messages, 1:1 huddles, and basic AI features, but it caps searchable message history at 90 days and limits you to about 10 app integrations. Past that, the Pro plan starts at $7.25 per user per month billed annually.

### How much does Slack cost?

Free is $0. Pro is $7.25/user/mo billed annually (or $8.75 monthly). Business+ is $12.50/user/mo annually (or $15 monthly) and adds SSO, compliance exports, and 24/7 support. Enterprise+ (formerly Enterprise Grid) is custom-quoted for large organizations and commonly lands in the low-to-high-$20s per user per month in negotiated deals.

### Is Slack SOC 2 and HIPAA compliant?

Yes. Slack maintains SOC 2 Type II (and SOC 3), ISO 27001, and is FedRAMP Moderate authorized. It supports GDPR and can be configured for HIPAA, including handling of electronically protected health information on eligible plans. Single sign-on via SAML is available, with SCIM provisioning on higher tiers. Check Slack's trust pages for the current scope before a regulated deployment.

### Slack vs Microsoft Teams, who is it for?

Slack tends to win for mixed-stack and Google Workspace teams that value the deepest third-party integration ecosystem and a cleaner messaging experience. Microsoft Teams is usually the default for organizations already paying for Microsoft 365, because Teams is bundled in and the effective marginal cost is near zero. Budget and existing stack drive the choice more than raw feature parity.


## Sources

- [G2: Slack reviews](https://www.g2.com/products/slack/reviews): rating 4.5/5 and review count 39,074, read live
- [Capterra: Slack](https://www.capterra.com/p/135003/Slack/): rating 4.7/5, 24,116 reviews, sub-scores, demographics, pricing tier names
- [Gartner Peer Insights: Slack (Salesforce)](https://www.gartner.com/reviews/product/slack-1244000344): rating 4.6/5 across 7,502 ratings, read live
- [Wikipedia: Slack (software)](https://en.wikipedia.org/wiki/Slack_(software)): founding, founders, 2013 launch, 2019 direct listing ($19.5B), $27.7B Salesforce acquisition
- [Wikipedia: Slack Technologies](https://en.wikipedia.org/wiki/Slack_Technologies): Tiny Speck origin (2009), HQ, ticker WORK, acquisition close July 21 2021
- [LinkedIn: Slack company page (About)](https://www.linkedin.com/company/tiny-spec-inc/about/): industry, company size band (1,001-5,000), HQ (Salesforce Tower, 415 Mission St), specialties
- [TechCrunch: Slack confirms $427M at $7.1B valuation](https://techcrunch.com/2018/08/21/slack-confirms-it-has-raised-427m-at-a-post-money-valuation-of-over-7-1b/): Series H, Dragoneer and General Atlantic
- [CNBC: Slack worth over $5B after $250M SoftBank investment](https://www.cnbc.com/2017/09/18/slack-worth-over-5-billion-after-250-million-investment-led-by-softbank.html): Series G, SoftBank Vision Fund, $5.1B valuation
- [Salesforce IR: Salesforce completes acquisition of Slack](https://www.salesforce.com/news/press-releases/2021/07/21/salesforce-slack-deal-close/): acquisition closed July 21, 2021, ~$27.7B
- [SEC: Salesforce Form 10-K (FY2026)](https://www.sec.gov/Archives/edgar/data/0001108524/000110852426000060/crm-20260131.htm): 83,334 total Salesforce employees as of Jan 31, 2026
- [TechForce: Denise Dresser to OpenAI, Rob Seaman interim CEO](https://www.techforceservices.com/news/salesforce-owned-slack-appoints-denise-dresser-as-new-ceo/): leadership change (CEO transition, Dec 2025)
- [Slack: Pricing](https://slack.com/pricing): plan names Free/Pro/Business+/Enterprise+, 90-day free history, 10-app limit
- [Slack: Trust / Compliance](https://slack.com/trust/compliance): SOC 2 Type II, SOC 3, ISO 27001, GDPR, HIPAA, FedRAMP Moderate