This chapter provides concise introductions to various background topics. You’re welcome to either read them all up front or individually as you go along—at the beginning of a section, you’ll find a list of topics it assumes knowledge of, like the Anywhere: HTTP section, which has two listed:
Background: HTTP, JSON
Some topics, like Git and Node, are necessary for following along with the coding. Others, like Tokens vs. sessions, are nice to know, but not essential.