JSON
In depthProtocol / format
Also known as: JavaScript Object Notation
Lightweight data-interchange format and the standard for API communication on the web.
JSON, explained
Written by EduVerseWhat it is
JSON (JavaScript Object Notation) is a text format for structured data. It has just a few building blocks: objects in curly braces with keys and values, arrays in square brackets, strings, numbers, true, false and null. Its syntax comes from JavaScript, but almost every language can read and write it.
Why teams use it
Systems written in different languages need a shared way to pass data around. JSON is quick to learn, readable by people and supported in practically every language. Compared with XML it’s shorter and maps directly onto objects and arrays, though it allows no comments and has no date type.
An example from work
Your fetch call fails with a SyntaxError about an unexpected token “<” when you call response.json(). The server didn’t send JSON at all: it returned an HTML page, and that < is the start of <!DOCTYPE html>. The Network tab shows the real cause, often a wrong URL or a server error.
Our own explanation, not a quote from the book.
In the book
Sentences from The Software Realm, Decoded that mention JSON, exactly as printed.
1 more passages about JSON in the full book
Read every conversation where JSON comes up, with the interactive slides and demos.
Where it fits
Data format for REST APIs and configuration files
Coverage in the book
Covered in depth: multiple pages with explanations, examples and simulations.
