DevGizmo

JSON Formatter & Validator

Format, minify or validate JSON — with clear syntax error messages.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight, human-readable data-interchange format. It is derived from JavaScript object syntax but is language-independent, with parsers available in virtually every programming language. JSON is the de-facto standard for REST API responses, configuration files, and data serialisation in modern software development.

Format (Pretty-Print)

The formatter parses the raw JSON and re-serialises it with consistent indentation (2 or 4 spaces). This makes nested structures easy to read and diff. Because it re-parses the input first, it also normalises quirks such as duplicate keys or inconsistent spacing.

Minify

Minification strips all unnecessary whitespace — newlines, spaces between tokens — to produce the most compact valid JSON string. This is useful when transmitting JSON over a network or embedding it in logs where byte size matters. Minified JSON is parsed identically to formatted JSON; only human legibility is affected.

Validate

The validator attempts to parse the input and reports either Valid JSON or a native browser SyntaxError with the exact position of the first error. Common mistakes caught include: trailing commas, single-quoted strings, unquoted keys, and comments (none of which are permitted by the JSON specification).