Cal Henderson

Callum James Henderson-Begg (born 17 January 1981), known as Cal Henderson, is a British computer programmer and author based in San Francisco... Henderson is best known as the co-founder and chief technology officer at Slack.com, as well as co-owning and developing the online creative community B3ta[3] with Denise Wilton and Rob Manuel; being the chief software architect for the photo-sharing application Flickr[4] (originally working for Ludicorp[5][6] and then Yahoo); and writing the book Building Scalable Web Sites [7] for O'Reilly Media. https://en.wikipedia.org/wiki/Cal_Henderson