Cal Henderson

Founder

Co-founder and CTO of Slack. Previously built and scaled Flickr's infrastructure. Began contributing to Stewart Butterfield's projects from England in 2001, initially paid with Amazon wishlist items. Author of 'Building Scalable Web Sites' (O'Reilly, 2006). Emigrated from England to Canada to join the team.

Overview

Companies
1
Roles
Founder

Companies

1 company
Slack $1.4B
Acquired Founder

Workplace messaging and collaboration platform that transformed business communication. Originally built as an internal tool at Tiny Speck during development of the game Glitch, then pivoted to become the fastest-growing enterprise software company in history.

Founder data is compiled from company records, public announcements, and verified sources. Roles reflect current or most recent known positions.