Where does Cal Henderson work?

Cal Henderson is Co-founder & CTO of Slack.

Where did Cal Henderson go to school?

Cal Henderson studied at Birmingham City University (BSc, Software Engineering); Sharnbook Upper School.

Cal Henderson

Unicorn founder

Co-founder & CTO at Slack

San Francisco, CA

FoundedSlack$7.1B

Find your path to Cal

66 people in our graph share verified history with Cal — schools, employers, funds. One of them is your warm intro.

Luke AlvarezunlockedCal: together at EMAP (2001)

×9Cal: together at Slack

×2Cal: together at Birmingham City University

About

Cal Henderson co-founded Slack in 2013 and has been its CTO throughout, having previously been an early engineer and architect at Flickr with Stewart Butterfield. He built the real-time messaging infrastructure that carried Slack from launch through a 2019 direct listing and the $27.7B Salesforce acquisition in 2021, and wrote Building Scalable Web Sites.

Co-founder & CTO at Slack

Intro paths

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In turn, Cal can intro founders to Slack's investors below.

Slack's investors · 43

1991 VenturesLondon · $504K checks AccelPalo Alto · $1.6M – $70M checks ACME CapitalSan Francisco Acrew CapitalSan Francisco · $1M – $15M checks Aglae VenturesParis · $108K – $5.4M checks Altos VenturesBurlingame · $1M – $3M checks Andreessen HorowitzMenlo Park · $500K – $50M checks Atlassian Ventures$1M – $5M checks Bloomberg BetaSan Francisco · $25K – $1M checks Coatue ManagementNew York · $1M – $20M checks Comcast VenturesNew York · $2M – $15M checks Craft VenturesSan Francisco · $50K – $50M checks EQUIAMSan Francisco · $1M – $10M checks Felicis VenturesSan Francisco · $500K – $15M checks FundersClubSan Francisco · $250K – $5M checks Global Founders CapitalBerlin · $637K – $32M checks Glynn Capital ManagementMenlo Park GP BullhoundLondon GV (Google Ventures)Mountain View · $250K – $50M checks High AlphaIndianapolis IVP (Institutional Venture Partners)San Francisco · $15M – $75M checks Khosla VenturesMenlo Park · $5K – $50M checks Kleiner PerkinsMenlo Park · $500K – $15M checks Light Street CapitalPalo Alto Lowercase CapitalJackson MicroVenturesAustin · $150K – $1M checks Moonshots CapitalAustin · $5K – $2.5M checks Mudita VentureDetroit · $500K – $1M checks Next Play VenturesMenlo Park · $100K – $5M checks NFXSan Francisco · $250K – $5M checks · since 2021 Night CapitalCapitola Norwest Venture PartnersMenlo Park · $10M – $30M checks · since 2021 Notable CapitalSilicon Valley · $5M – $50M checks S32Palo Alto Section 32Palo Alto Slow VenturesSan Francisco · $50K – $1M checks SoftBank Vision FundLondon Spark CapitalSan Francisco · $500K – $25M checks SV AngelSan Francisco TriplePoint CapitalMenlo Park · $250K – $10M checks · since 2021 Unanimous CapitalMenlo Park Westbound Equity PartnersPalo Alto · $750K – $2M checks · since 2021 Wireframe VenturesSan Francisco · $500K – $2M checks

Co-founders at Slack

Stewart ButterfieldCo-founder & CEO

Experience

Slack Technologies, IncCo-founder & CTO2009 — 2024San Francisco, CA
FlickrHead of Engineering2003 — 2009San Francisco Bay Area
EMAPDirector of Technology2001 — 2004Greater London, England, United Kingdom

Skills & more

CMS3JavaScript27Flash3APIs1Mobile Applications7jQueryPHP21MySQL4Web Applications13HTML 5Web Development37Scalability16

+12 more

SubversionUser ExperienceProgrammingSoftware DevelopmentCSSHTMLWeb ServicesRubyScrumFront-endOOPActionScript

From Cal's professional profile.

Podcasts & interviews

featuring Cal Henderson

Slush AgAIn | Cal Henderson (Slack) & Laura Modiano (OpenAI)

Slush

Cal Henderson: Co-founder @Slack, Workplace Productivity & Organizational Alignment | Slush 2024

Slush

Slack’s Founding Story | Cal Henderson (Slack) & Sarah Cannon (Coatue) | Slush 2023

Slush

#54 - Cal Henderson // CTO @ Slack - alphalist.CTO Podcast - For CTOs and Technical Leaders

alphalist

Slack CTO and Co-Founder Cal Henderson, 2019 GeekWire Cloud Summit

GeekWire

Building Software That People Love: Lessons from Cal Henderson, Slack Co-founder & CTO

Slush

Frequently asked questions

Who is Cal Henderson?: Cal Henderson co-founded Slack in 2013 and has been its CTO throughout, having previously been an early engineer and architect at Flickr with Stewart Butterfield. He built the real-time messaging infrastructure that carried Slack from launch through a 2019 direct listing and the $27.7B Salesforce acquisition in 2021, and wrote Building Scalable Web Sites.
Where does Cal Henderson work?: Cal Henderson is Co-founder & CTO of Slack.
What companies did Cal Henderson found?: Cal Henderson founded Slack.
Where did Cal Henderson go to school?: Cal Henderson studied at Birmingham City University (BSc, Software Engineering); Sharnbook Upper School.
What podcasts and interviews feature Cal Henderson?: Tracked appearances include "Slush AgAIn | Cal Henderson (Slack) & Laura Modiano (OpenAI)", "Cal Henderson: Co-founder @Slack, Workplace Productivity & Organizational Alignment | Slush 2024", "Slack’s Founding Story | Cal Henderson (Slack) & Sarah Cannon (Coatue) | Slush 2023", and 3 more.

Founder mafias

Birmingham City University mafia5

Also came through, then founded or led a company.

Oana Andreea JingaBA (Hons) Media and CommunicationFounded Dexory Callum BrightingMSc Games DevelopmentFounded Netspeak Paul HemingBScFounded C-Link Chris BarberBachelor of Science (BSc)Founded C-Link

Same school

Also attended Birmingham City University18

Fareez TokaranHuman Resource and Administration Manager at TNBAura David ThompsonGeneral Partner at 415 Capital Hugues Le MaireStrategic Partnerships, France at Speedinvest Amy WestwoodGroup Brand Manager at Mercia Ventures Rebecca SykesPartner at Brandtech Ventures Tom JonesManaging Director at Draper Triangle

+ 12 more

Shared employers

Also worked at Slack Technologies, Inc62

Mamoon HamidPartner at Kleiner Perkins Hans TungManaging Partner at Notable Capital Stewart ButterfieldCo-founder of Slack and Flickr Dana ChamorroVice President, Technology at Redpoint Ventures Neha JewalikarDirector of Communications at Scale Venture Partners Glenn SolomonInvestor at GGV Capital

+ 56 more

Also worked at Flickr6

Caterina FakeInvestor at Yes VC Maijid MoujaledCo-Founder & President at Chipper Cash Kyle ArchieFounder at Lysto Manuel Diaz-GranadosFounder at Lysto Andrew StadlenInvestor at Raisewell Ventures Pouria SanaeExecutive Officer, Director at IX Layer

Also worked at EMAP4

Luke AlvarezFounder & Managing General Partner at Hiro Capital Lisa ThornleyMarketing Manager at Clean Growth Fund Dawn BebeFounder at Crowdfunder Tessa ClarkeFounder at Olioapp