secretleaders | Slack: Cal Henderson – An Engineer’s Fairytale Story

Slack: Cal Henderson – An Engineer’s Fairytale Story

Welcome back to series 4 – what a season have we got lined up for you!

Kicking us off is Cal Henderson, co-founder and CTO of one of this decade’s most famous tech companies – the team communications platform the majority of companies couldn’t be without, Slack.

But Cal hasn’t always been CTO of Slack, he cut his teeth as co-founder and VP Eng for Glitch, a web-based massively multiplayer game, before that, he was the Director of Engineering for Flickr at Ludicorp (where he first met Slack fellow co-founder Stuart Butterfield) and then Yahoo.

As you will shortly hear, Cal is considered to be one of Britain’s finest exports. Although it’s probably fair to say that he divides people much less than Marmite. Now residing in San Francisco where Slack is headquartered, Cal grew up in the humble county of Bedfordshire, England.

After completing a computer science degree from Birmingham City University, he moved to the US in 2003, but not before landing a job after hacking into the email system of the company he wanted to work for and telling his future bosses that he could help them fix the problems they were having.

This is a guy who it would appear got lucky, several times over. But in truth, all of Cal’s success has been down to hard work and his first love – computers.

“From the first time I got a computer, I was like, this is what I want to do with the rest of my life. This is what I want to do for work.”

We chat about:

  • How he met Stewart Butterfield
  • How he got a job through hacking the company he wanted to work for
  • Why investors Accel and Andreessen Horowitz didn’t mind them failing
  • How on Slack launch day they had 8,000 companies sign up to use Slack
  • The advice he’d give to his 15 year old self



The Secret Leaders podcast features interviews with key figures from the UK tech and creative ecosystem. From entrepreneurs (both early and latter stage), to journalists, VCs - and even royalty - the series profiles those who have helped shape the nation's culture of innovation and growth.