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§ Public · San Francisco, CA, USA
Building the workplace collaboration hub
Communication is fundamental to human beings. Yet it’s rare that a company changes how we connect and work together, much less how we delight one another. (With emoji or otherwise). Slack has somehow managed to do just that. It’s made work more fun for millions of people.
In the process, it’s made work so much better, as well.
What Stewart, Cal, and the Slack team have accomplished is more than remarkable. It’s invaluable. With no hyperbole, their achievement is simply life-changing. The pivot from Glitch to Slack by now may be a familiar tale, but let’s not forget just how much courage, vision, and bull’s-eye execution it required. Pivots rarely pan out. The fact that this one found lasting success owes to the founders’ extraordinary foresight and entrepreneurial grit.
Slack holds a special place in our hearts and in our own firms’s history. It is literally where three Kleiner Perkins partners (Mamoon Hamid, John Doerr, and Ilya Fushman) first worked together. That collaboration became the basis of our partnership at Kleiner Perkins today.
Slack has raised $2.0B across 13 funding rounds.
Key people at Slack.
Slack was founded in 2013 by Stewart Butterfield (CEO & Co-founder) and Cal Henderson (Co-Founder and CTO) and Eric Costello (Co-founder, Client Lead) and Serguei Mourachov (Co-Founder and Principal engineer).
Slack has raised $2.0B in total across 13 funding rounds.
# Slack: Building the Workplace Collaboration Hub
Slack is a channel-based messaging platform designed to transform how teams communicate and collaborate in the workplace.[7] The company serves businesses of all sizes, from startups to enterprises, by providing a centralized hub for real-time communication, file sharing, and integration with productivity tools. Rather than relying on fragmented email chains and scattered conversations, Slack consolidates team communication into organized channels and direct messages, fundamentally addressing the inefficiency and information silos that plague traditional workplace communication.
The platform's growth trajectory has been extraordinary. Slack achieved unicorn status—a $1 billion valuation—in record time, and the company ultimately sold to Salesforce for $27.7 billion, validating the massive market opportunity for workplace collaboration tools. Today, Slack stands as a defining example of how a well-executed pivot from a failing venture can create one of the most valuable software companies in the world.
Stewart Butterfield's path to founding Slack was unconventional and shaped by repeated entrepreneurial pivots. In 2002, Butterfield co-founded Ludicorp with his then-wife Caterina Fake, initially working on an ambitious multiplayer online game called *Game Neverending*.[3] When that project failed to gain traction, the team pivoted to create Flickr, a photo-sharing platform that became a massive success and was acquired by Yahoo in 2005.[1]
After leaving Yahoo in 2008, Butterfield was ready for another challenge. In 2009, he co-founded Tiny Speck alongside Eric Costello, Cal Henderson (Flickr's original chief software architect), and Serguei Mourachov—all former Flickr employees who had worked at Yahoo following the acquisition.[4] The team set out to build another multiplayer game called Glitch, a whimsical 2D web-based game that launched in September 2011.[3]
However, Glitch struggled to attract a sustainable user base. The game was expensive to operate and failed to gain sufficient traction in the market. Yet during Glitch's development, the team had created an internal communication tool to coordinate more effectively across their geographically distributed team—Butterfield and Mourachov were based in Vancouver, Henderson in San Francisco, and Costello in New York City.[4] As Glitch's inevitable failure became clear, the team recognized that this internal chat tool possessed significant value beyond their own startup.
Between late 2012 and early 2013, Butterfield made the bold decision to pivot Tiny Speck entirely toward enterprise software.[4] In August 2013, he announced the public release of Slack, positioning it as an instant-message-based team communication tool.[3] The name itself was an acronym: "Searchable Log of All Conversation and Knowledge."[1] This pivot from gaming to enterprise software was audacious—few gaming industry CEOs successfully transition to B2B software—but it proved transformative.
Slack's founding team deliberately rejected the sterile, corporate aesthetic of traditional business software. Drawing lessons from their gaming background, they prioritized making every interaction "interesting, fun and irreverent."[3] The platform featured a playful name, bright and cheerful branding, custom emoji support, and voice & video calling capabilities that made workplace communication feel engaging rather than obligatory.[1] This design philosophy became a competitive moat—Slack felt fundamentally different from the enterprise software users expected.
Rather than relying on traditional enterprise sales, Butterfield personally begged friends at other startups to test Slack and provide feedback before launch.[1] This grassroots, product-driven approach shaped the platform based on real user needs. The company took a cheeky full-page newspaper ad welcoming Microsoft to the market when it launched Teams, demonstrating confidence and brand personality.[1] This unconventional marketing resonated with the startup community and created organic momentum.
Slack prioritized security and reliability from day one to gain business customers' trust—a critical differentiator for enterprise adoption.[1] This foundation enabled rapid scaling without the security concerns that plague many consumer-first products attempting to serve businesses.
Slack's architecture emphasized integration with other software tools, recognizing that teams use multiple applications. This openness created a powerful network effect as developers built integrations and bots, expanding Slack's utility far beyond its core messaging functionality.
Slack emerged at a pivotal moment in workplace technology evolution. The rise of remote work, distributed teams, and the decline of email as a primary communication medium created a massive market opportunity. Slack rode the wave of cloud-based SaaS adoption, mobile-first computing, and the growing recognition that workplace productivity software needed to be as intuitive and engaging as consumer applications.
The company's success validated a broader thesis: enterprise software could be beautiful, delightful, and user-centric. Before Slack, many businesses accepted clunky, difficult-to-use tools as inevitable. Slack demonstrated that companies would pay premium prices for software that actually improved their daily experience. This influenced an entire generation of enterprise startups to prioritize design and user experience.
Slack also catalyzed the platform economy within enterprise software. By opening its API and encouraging third-party developers to build integrations and bots, Slack transformed itself from a standalone messaging tool into a workplace operating system—a central hub through which teams could coordinate work across multiple applications. This platform approach created powerful network effects and switching costs that protected Slack's market position.
The company's $27.7 billion acquisition by Salesforce in 2021 signaled that workplace collaboration had become a core strategic asset for enterprise software vendors. Rather than remaining independent, Slack's value was maximized as part of Salesforce's broader ecosystem, demonstrating how collaboration tools had become essential infrastructure for modern business.
Slack's journey from a failed gaming startup's internal tool to a $27.7 billion acquisition represents one of the most successful pivots in startup history. The company proved that timing, product-market fit, and design excellence could overcome the odds—even when your original business is collapsing.
Looking forward, Slack's evolution within Salesforce will likely focus on deeper integration with CRM and business processes. Rather than remaining a standalone communication platform, Slack will increasingly become the interface through which teams interact with Salesforce's broader ecosystem. The rise of AI-powered workplace assistants will be critical—Slack's position as the central hub for team communication makes it an ideal platform for AI agents that understand context and can automate workflows.
The broader lesson Slack teaches the tech ecosystem is enduring: constraints breed creativity. A gaming startup's need to communicate across distributed teams created a tool that transformed how millions of people work. In an era of increasingly specialized, point-solution software, Slack's success suggests that platforms that become genuinely indispensable to daily workflows—regardless of their origin story—will command outsized value. The company's influence on workplace collaboration will likely persist for decades, even as the specific form of that collaboration continues to evolve.
Key people at Slack.
Slack was founded in 2013 by Stewart Butterfield (CEO & Co-founder) and Cal Henderson (Co-Founder and CTO) and Eric Costello (Co-founder, Client Lead) and Serguei Mourachov (Co-Founder and Principal engineer).
Slack has raised $2.0B in total across 13 funding rounds.
Slack's investors include Dragoneer Investment Group, General Atlantic, 10100, 2xN, Kevin Hartz, Accel, ACME Capital, Andreessen Horowitz, Atomic, Benchmark, Cota Capital, Craft Ventures.
Slack has raised $2.0B across 13 funding rounds. Most recently, it raised $430.0M Series H in August 2018.
