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What is Slack?
Slack is a business messaging and collaboration platform built around channels, direct messages, and app integrations. Slack was acquired by Salesforce in 2021.
Slack Fast Facts
- Paid customers: 200k+ (Slack.com “About” page)
- Fortune 100 adoption: 77 of the Fortune 100 use Slack (Slack.com “About” page)
- Global footprint: 150+ countries have daily active users in Slack (Slack.com “About” page)
- Historical daily active users: exceeded 10 million DAU during the three months ended Jan. 31, 2019 (Slack SEC S-1)
- Historical messaging volume: 1+ billion messages sent in Slack during the week ended Jan. 31, 2019 (Slack SEC S-1)
Source: Slack.com/About |
Source: Slack SEC S-1 (2019)
Slack Statistics and Facts
Current (Slack.com)
| Paid customers | 200k+ |
| Fortune 100 usage | 77 of the Fortune 100 use Slack |
| Countries with daily active users | 150+ countries |
Historical (SEC Filing, January 2019 Snapshot)
The metrics below are from Slack’s public SEC S-1 filing and reflect a specific historical period (not a current real-time dashboard).
| Daily active users (DAU) | Exceeded 10 million (three months ended Jan. 31, 2019) |
| Organizations (3+ users) | 600,000+ (as of Jan. 31, 2019) |
| Paid customers | 88,000+ (as of Jan. 31, 2019) |
| Free-plan organizations | 500,000+ (as of Jan. 31, 2019) |
| Messages sent | 1+ billion messages (week ended Jan. 31, 2019) |
| Weekly active use time | 50+ million hours (week ended Jan. 31, 2019) |
| Typical paid user: connected time | 9 hours connected per workday (at least one device) |
| Typical paid user: active use time | 90+ minutes actively using Slack per workday |
| International mix | More than half of daily active users were outside the U.S. |
| Employees | 1,664 (as of Jan. 31, 2019) |
Slack SEC S-1 (2019): Operating metrics and engagement
Funding and Valuation (Historical)
- Series H investment added: $427 million (announced Aug. 2018)
- Total funding raised at that time: $1.268 billion (Series H announcement states $841M previously raised + $427M new)
- Reported post-money valuation: more than $7.1 billion (Series H announcement)
Slack: Series H financing announcement
Important Note on “How many people use Slack?”
Slack’s older public reporting often referenced DAU/WAU counts (for example, “exceeded 10 million daily active users” in early 2019). In more recent years, Slack’s public materials more consistently emphasize paid customers and enterprise adoption rather than publishing a continuously updated DAU total. To keep this page verifiable, the “current” metrics above use Slack’s official About page, while DAU and other engagement figures are presented as dated historical snapshots from SEC filings.
Sources / References
