JSON Formatter
Format, minify, and validate JSON
What is JSON?
JSON (JavaScript Object Notation) is a lightweight, language-agnostic data-interchange format that became the de facto standard for web APIs, configuration files, and structured logs. It uses a small, predictable grammar — strings in double quotes, numbers, booleans, null, arrays, and objects — that every modern language can parse natively.
Formatting (pretty-printing) makes JSON readable; minifying strips whitespace to shrink it for transmission or storage. Validating parses the input and reports the first syntax error your browser's JSON engine encounters, which is what runtime code does under the hood.
Examples
{"name":"Alice","scores":[95,88,73],"active":true}{
"name": "Alice",
"scores": [
95,
88,
73
],
"active": true
}{
"id": 1,
"tags": ["json", "tool"],
"meta": null
}{"id":1,"tags":["json","tool"],"meta":null}Frequently asked questions
What is JSON?
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It looks like a JavaScript object literal — keys in double quotes, values that can be strings, numbers, booleans, null, arrays, or other objects. JSON is the default format for most modern APIs.
What is the difference between formatted and minified JSON?
Formatted (or 'pretty-printed') JSON adds whitespace and line breaks for human readability. Minified JSON removes all whitespace to reduce file size — useful when transmitting JSON over the network or storing it in a database. Both forms are functionally identical to a parser.
What does the indent option do?
Indent sets the number of spaces used for each nested level when formatting. 2 spaces is the most common (used by JavaScript and many style guides). 4 spaces is also popular. Setting indent to 0 effectively minifies the output.
Why does my JSON show a parse error?
Common causes: trailing commas (not allowed in strict JSON), single quotes around strings (must be double quotes), unquoted keys, comments (JSON has no comment syntax), or special characters like NaN or Infinity (use null or stringified numbers instead).
Is my JSON uploaded anywhere?
No. Parsing, formatting, minifying, and validation all run entirely in your browser using the native JSON API. Your input never leaves your device, and Wenee logs nothing on the server — safe for use with sensitive payloads.
Can I use this for very large JSON files?
Yes — the limit is your browser memory. Most browsers comfortably handle JSON up to several megabytes. For multi-hundred-megabyte payloads, a desktop tool like jq is faster than any browser-based formatter.