GlassFish vs Wildfly: What are the differences?
GlassFish: The Open Source Java EE Reference Implementation. An Application Server means, It can manage Java EE applications You should use GlassFish for Java EE enterprise applications. The need for a seperate Web server is mostly needed in a production environment; Wildfly: A Java EE8 Application Server. It is a flexible, lightweight, managed application runtime that helps you build amazing applications. It supports the latest standards for web development.
GlassFish and Wildfly belong to "Web Servers" category of the tech stack.