JSON (JavaScript Object Notation) is a lightweight text format for structured data: objects as key-value maps, arrays as ordered lists, and values like strings, numbers, booleans, and null.
Readable indentation helps humans review configs, API responses, and fixtures. Minified JSON saves bytes on the wire; pretty JSON saves time when debugging.
The formatter parses your input first. If JSON is invalid, you will see an error pointing to the problem area instead of a beautified output until the syntax is fixed.
Yes. Use the minify option where available to produce a single-line compact JSON string for APIs or storage.
Very large payloads may be slower in the browser depending on your device. For huge files, consider streaming or server-side processing for best performance.
JSON requires double-quoted keys and strings, no trailing commas, and no comments. Object literals in JS are more permissive; valid JSON is a strict subset useful for interchange.
JSON maps cleanly to data structures in most languages, is easy to generate and parse, and is human-readable enough for logs and browser devtools.
Validation checks that text follows JSON grammar and sometimes that it matches a schema (expected keys and types). A formatter’s parse step is a basic syntax validation.
Trailing commas, single-quoted strings, unquoted keys, comments, and trailing text after a value break strict JSON. Fix these to match RFC 8259-style parsers.
All three represent structured data. JSON is minimal and ubiquitous in REST APIs; YAML adds readability features; XML is verbose and still common in enterprise and documents.