Cal Henderson
Mid National Level Public Record
Editorial estimate, not verified fact — DisclaimerCo-Founder & Former Chief Technology Officer of Slack
Data Confidence: 78% · Sources: 3 · Last Updated: Sep 18, 2026
- Net Worth ▲
- Estimated $200M – $700M
- Reach ▲
- 35.0M people
- Power ▲
- Commanded technical strategy and engineering architecture powering Slack, which scaled to tens of millions of daily users and culminated in a $27.7 billion acquisition by Salesforce in 2021.
- Influence ▲
- Transformed modern workplace messaging paradigms through Slack's platform architecture and contributed to widely adopted open web protocols including oEmbed and early OAuth specifications.
- Network ▲
- Maintains technical and executive networks spanning Silicon Valley startup founders, venture capital circles, and executive leadership at Salesforce and Yahoo.
- Legacy ▲
- Authored the 2006 technical book 'Building Scalable Web Sites' for O'Reilly Media and architected enterprise communications software used daily by millions of global knowledge workers.
- Trajectory ▲
- Stable — first assessment on record.
About
Cal Henderson is a British computer programmer, author, and technology executive based in San Francisco, California. He co-founded Slack (originally Tiny Speck) in 2009 alongside Stewart Butterfield and served as its Chief Technology Officer for 15 years. Before Slack, Henderson was the chief software architect at Flickr, led engineering initiatives following its acquisition by Yahoo in 2005, and co-created early web standard protocols including oEmbed.
Known For
Co-founding and serving as Chief Technology Officer of workplace communication platform Slack.
Connections
Leadership & Employment
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- Wikipediacorroborated
- Slushcorroborated
- Iamcalcorroborated