informational guide · Updated 2026-08-12
What is JSON?
Learn what JSON is, why APIs use it, and how to format and validate JSON safely in your browser.
JSON in plain language
JSON (JavaScript Object Notation) is a text format for structured data. It looks a bit like JavaScript object literals but follows stricter rules: double-quoted keys, no trailing commas, and a limited set of value types.
Objects, arrays, and types
APIs use JSON because it is readable by humans and easy for machines to parse across languages. Config files, webhook bodies, and mobile apps frequently exchange JSON payloads.
Where JSON shows up
Common building blocks include objects (`{}`), arrays (`[]`), strings, numbers, booleans, and null. Nesting lets you represent trees of data without inventing a new format each time.
Format vs validate
Formatting (beautifying) changes whitespace so people can read nested keys. Validating checks whether a parser can accept the document. Pretty JSON can still be invalid if commas or quotes are wrong.
Safety tips
Never paste production secrets into public tools. Prefer fixtures that mirror shape without real tokens. On Utila, format with the JSON Formatter, then confirm with the JSON Validator.
Primary tool: JSON Formatter
