JSON Formatter & Validator - Format, Validate and Minify JSON
Format, validate and minify JSON directly in your browser. Includes syntax highlighting, clear error messages and directly copyable results. Ideal for debugging API responses, cleaning up JSON configurations and reducing JSON payload sizes.
Note:All generated data is entirely fictional and not suitable for use as real personal information.
JSON format and validation
JSON (JavaScript Object Notation) is a lightweight, human-readable data interchange format defined in RFC 8259. Despite the name, JSON is language-independent and is used across virtually every programming language and platform as the de facto standard for REST API payloads, configuration files, and data storage.
JSON data types
- Object — key-value pairs wrapped in
{ }. Keys must be double-quoted strings. - Array — ordered list of values wrapped in
[ ]. - String — double-quoted text. Escape sequences:
\n\t\"\\. - Number — integer or floating point. No NaN, no Infinity, no leading zeros.
- Boolean — lowercase
trueorfalse. - Null — lowercase
null.
Common JSON errors
- Trailing commas — JSON does not allow a comma after the last element in an object or array. This is valid in JavaScript but invalid in JSON.
- Single quotes — All strings and keys must use double quotes. Single-quoted strings are not valid JSON.
- Unquoted keys — Object keys must be quoted strings:
"name": "Alice"notname: "Alice". - Comments — JSON does not support comments. Use JSONC or JSON5 variants if you need them.
Beautify vs minify
Beautified JSON is indented and line-separated, making it easy to read and debug. Minified JSON removes all whitespace to reduce payload size for production APIs. A typical REST API should serve minified JSON; use a formatter for debugging. Minification can reduce JSON size by 20–40% depending on content.