This document discusses building serverless web applications using Apache OpenWhisk. It defines serverless and function as a service (FaaS), noting that servers are hidden from developers and code is executed on-demand through event triggers. It explains that serverless is often cheaper than other options since developers only pay for the duration of code execution. It also notes that serverless functions can leverage existing JavaScript skills of web developers. The document then demonstrates creating and invoking JavaScript actions on OpenWhisk, including creating web actions, API management with OAuth, and integrating an Angular application to access protected actions.