Cal Henderson is the co-founder and CTO of Slack. He oversees Slack’s world-class engineering team and sets the technical vision for the company. Previously, Cal built and led the engineering teams at Flickr, through its acquisition by Yahoo!. An experienced technology leader and a popular speaker on engineering scalability, he authored the best-selling O’Reilly Media book Building Scalable Websites. Cal was also a pioneer in the use of web APIs and created the basis for OAuth and oEmbed, now used by YouTube and many others.