Slack

Workplace messaging and collaboration platform, a Salesforce company since July 2021. Salesforce paid about $27.7 billion for it.

Industry: Workplace messaging and collaboration software | Location: San Francisco, United States | Founded: 2009

About Slack

Slack is a workplace messaging and collaboration platform. Its website identifies the operating entity as Slack Technologies, LLC, a Salesforce company, and says the platform has more than 200,000 paid customers, is used by 77 of the Fortune 100 and has daily users in more than 150 countries. Those figures are undated on the page, which was read in October 2026.

Wikipedia reports that the company began in 2009 in Vancouver as Tiny Speck under Stewart Butterfield, built the online game Glitch, and used Slack as an internal tool during that work before renaming itself Slack Technologies in August 2014. Butterfield was chief executive and co-founder when Salesforce agreed to buy the company in 2020 and when the deal closed in 2021. Fortune reported that Salesforce chief executive Marc Benioff named Denise Dresser chief executive of Slack in 2023. In December 2025 OpenAI hired her as its chief revenue officer, and Slack's chief product officer, Rob Seaman, took over her responsibilities on an interim basis.

The website lists channels, Slack Connect, huddles, canvases, lists, Slackbot, enterprise search and a workflow builder, plus AI features and Agentforce, Salesforce's agent platform. It cites more than 2,500 apps. The trust page lists ISO/IEC 27001, 27017, 27018, 27701 and 42001 certifications, SOC 2 Type II and SOC 3 reports, and FedRAMP authorization, with a separate GovSlack offering.

According to Wikipedia, Slack raised $120 million at a $1.2 billion valuation in October 2014 and $250 million, mostly from SoftBank Vision Fund, in September 2017, which brought total funding to $841 million. It bought Screenhero in 2015 and the HipChat and Stride technology from Atlassian in 2018. It listed on the New York Stock Exchange by direct listing on 20 June 2019 under the symbol WORK.

Salesforce announced on 1 December 2020 that it would acquire Slack at an enterprise value of about $27.7 billion, with each share receiving $26.79 in cash and 0.0776 Salesforce shares. Salesforce announced completion on 21 July 2021. A TechScoop article of 18 June 2026 cited Slack as an earlier example of product-led growth.

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