Careers at Slack


Slack develops and maintains a software-as-a-service platform which is designed to increase productivity and efficiency for teams and organisations working on collaborative projects.


Slack was founded in 2009 by Stewart Butterfield (“Butterfield”), Cal Henderson (“Henderson”), Eric Costello (“Costello”) and Serguei Mourachov (“Mourachov”). The team first began working together in 2002 to develop Game Neverending, an online fantasy game with integrated social media elements. While the game did not prove successful in the post-dotcom bubble era, Butterfield recognised that the team still had useful code. They spun off some of the game code to be used to share photos online. The standalone service, which became known as Flickr, grew quickly and was ultimately sold to Yahoo in 2005 for $25 million.

After several years working at Yahoo, the team reassembled to develop Glitch, another social fantasy adventure game, which received funding from Accel Partners and Andreessen Horowitz. While Glitch also proved unsuccessful, it led to the creation of Slack. During the game’s development the team communicated via internet relay chats (“IRC”) that organise conversations into channels. Throughout the development process the team had designed its own IRC application and vowed never to embark on any major projects without a similar tool. This developed into the Slack concept.

Slack received $1.5 million in seed funding in 2009. The Company has since raised a total of just under $540 million in nine rounds of funding from 21 investors, including Comcast Ventures, GGV Capital and Slow Ventures. The $160 million received by Slack in April 2015 saw the Company valued at approximately $2.8 billion.

Business model of Slack

Customer Segments

Slack’s software platform is designed primarily to serve small, medium and large businesses, particularly those that require frequent collaboration on team projects. While the product is not targeted at any one particular sector, the majority of Slack’s high-profile customers come from within the tech and media industries.

The Company’s customers, however, also include companies from within the travel, academic and retail spaces. Slack’s major customers include Airbnb, Dow Jones, LinkedIn, The Wall Street Journal, BuzzFeed and Ebay.

Slack also provides services at a discounted price to a number of charities and non-profits, including Canadian Feed the Children, Teach for America and Massachusetts Institute of Technology.

Value Propositions

Slack offers a completely free service to its basic users, which allows small team to access the Company’s platform at no cost and larger teams to try out the software before purchasing a plan. In its paid plans, the Company charges per actual active user rather than charging for unused user accounts.

The Slack platform enables users to collaborate on projects efficiently and conveniently, with a range of messaging and sharing services and access to the software available across multiple channels. The Slack platform also allows its users to fully customise its service with a wide range of third-party integrations and community-built integrations.


Slack’s software platform can be accessed directly through the Company’s website at The Company also provides desktop applications for Mac OS, Microsoft Windows and Linux, as well as mobile apps for iOS, Android and Windows Phone.

Slack also has a sales and support team which can be contacted directly for technical assistance and account management services.

Customer Relationships

Slack primarily operates as a self-service model. Following registration, users are granted access to the Company’s productivity platform and related services via desktop and mobile apps.

Slack provides ongoing technical assistance to its users via online tutorials and video guides, and interacts with customers through its own blog, podcast and social media accounts with Twitter and Facebook.

The customisation options available within the Slack platform are in part community-driven, with users developing their own integrations.

Larger users, in particular those wishing to use Slack across an entire organisation, require a greater degree of personal care and ongoing after-sale support from the Company’s sales and support teams.

Key Activities

Slack’s is primarily engaged in the development, maintenance and sale of software-as-a-service. The Company’s platform allows users to collaborate on team projects and interact with one another across desktop and mobile channels using messaging and sharing tools.

Slack also manages a number of partnerships with third-party application companies and software developers to provide multi-service integration for its users.

Key Partners

Slack’s main partners are application and software developers and third-party productivity and enterprise service providers, which work with the Company to develop multi-service integration.  Since releasing its API, Slack has integrated its platform with a number of leading productivity apps, including Google Drive, Trello, Dropbox, Github and Zendesk, among others.

Slack has also partnered with companies to increase productivity outside the workplace, working with Lyft, Foursquare and several other tech companies to allow Slack users to request car rides and find places to eat.

Key Resources

Slack’s key resources are its software platform, its API, its IT infrastructure and its personnel. While the Company’s proprietary technology is key, Slack has no patent applications registered with the US Patent and Trademark Office.

In order to develop, maintain and sell its product, Slack’s sales and marketing and research and development teams are key resources.

Slack also remains in its infancy and, while it is has grown quickly and is reported to be generating substantial revenue, it has not yet announced that it is profitable. Therefore, it is likely that the Company’s investors remain a key resource for its operations.

Cost Structure

Slack incurs costs in the maintenance and development of its software platform, both in the form of operating server space and data centres and in retention of its research and development teams.

The Company also accrues cost of sale, in part through the employment of its sales and marketing division, as well as costs related to the management of its various partnerships.

Revenue Streams

Slack generates revenue using a freemium software-as-a-service model. The Company’s enterprise software solutions are charged per actual user. This is in place of the traditional method of charging per seat, whereby a company would be charged for a certain amount of users regardless of whether all their available seats were used.

Slack offers four subscription plans, starting with a free plan designed for small teams and casual users. The first paid-for plan is the Standard package, which costs $6.67 per daily active person billed annually or $8 per person billed monthly and includes access to additional tools. The Plus plan, which comes with more tools and additional support services, costs $12.50 per user billed monthly or $15 per user billed annually. Slack is set to launch its fourth plan, the Enterprise plan, which will cover multiple teams across an entire organisation, with consolidated billing and administration. The plan does not have a fixed price and is likely to be negotiated on a case-by-case basis.

Our team

Stewart Butterfield,
Co-Founder and Chief Executive Officer

info: Stewart has served as Slack’s Chief Executive Officer since co-founding the Company in 2009. He has had a successful career within the technology sector. He began his career in 1999 as Director of Design at IT services company Communicate. He left this role after a year to join Gradfinder, a recruitment service, as Managing Director and Company Secretary, where he stayed until the company was acquired by Highwired in 2000. After working as a product design consultant for two years, Butterfield co-founded photo sharing website Flickr in 2002 where he served as Chief Executive Officer. Following the company’s acquisition by Yahoo in 2005, Butterfield was appointed Flickr’s General Manager and Senior Director of Product Management. He left this role to co-found Slack.

Cal Henderson,
Co-Founder and Chief Technology Officer

info: Cal has been Slack’s Chief Technology Officer since 2009. Prior to co-founding Slack, Henderson held a number of programming and web development roles, beginning with programming positions at Link Information Systems and 5emedia between 1999 and 2001. From 2001 to 2004 Henderson served as Technical Director at networking company eMap Special Web Projects, before joining Ludicorp Research and Development as its Director of Web Development. Prior to co-founding Slack he worked at Yahoo as Director of Engineering. Henderson also briefly owned his own software company, Kaius Software, which he left in 2005.

Eric Costello,
Co-Founder and Head of Software Client Development

info: Media coverage suggests that Costello leads Slack’s Software Client Development team. Prior to co-founding Slack he also led client development for browser-based video game Glitch and Flickr, where he first became involved with the members of the Slack team.

Serguei Mourachov,
Co-Founder and Server Lead

info: Serguei has led Slack’s Server team since the Company’s establishment in 2009. Prior to co-founding Slack he served as Principal Software Engineer for Flickr, under Yahoo, from 2005. There is little coverage of Mourachov’s earlier career.