Companies such as Netflix and CA Technologies rely on software co-developed by Neha Narkhede, which funnels data from disparate sources of information—web analytics, sales data, social media—into a single stream that employees can use to build or enhance their projects. The six-year-old technology, called Apache Kafka, is now available for free as an open-source program. It has become so integral to the tech world that Silicon Valley engineers brandish Kafka expertise on their resumes. Narkhede and her two co-creators, who developed Kafka while engineers at LinkedIn, decided early on not to profit from the software directly. But in 2014, they launched a company called Confluent that provides technical support, additional tools, and training for businesses on how to use it to best maximize its potential. Narkhede herself has become a global evangelist of the tool, and even coauthored the definitive guide to Kafka and stream processing, due out later this year.