JSON formatter
Turn compact or hard-to-read JSON into a consistently indented structure that is easier to review during API debugging, development and configuration work.
JSON Formatter & Validator
Beautify, validate or minify JSON instantly. Processing happens in your browser, so your JSON is not sent to our server.
InputPaste or edit JSON
OutputReady
Format, validate and minify JSON locally
Paste JSON into the editor or open a local .json file, then format it with 2 spaces, 4 spaces or tabs. The validator uses the browser's native JSON parser, and the minifier serializes valid data without unnecessary formatting whitespace.
JSON validator
Parse the input as standard JSON and report syntax errors. When the browser provides a character position, the tool also calculates a line and column to make the error easier to locate.
JSON minifier
Parse valid JSON and serialize it without indentation or unnecessary whitespace while preserving the represented data.
Structure statistics
After a successful parse, see rendered size plus counts for objects, arrays, keys and maximum nesting depth.
JSON syntax rules that commonly cause errors
Standard JSON requires double quotes around object keys and string values. Trailing commas are not allowed, comments are not part of the JSON standard, and brackets or braces must be correctly paired. Valid JSON values include objects, arrays, strings, numbers, booleans and null.
JavaScript object syntax can look similar to JSON but is not identical. Single-quoted strings, unquoted keys, functions, undefined, comments and trailing commas may be accepted in JavaScript contexts while still being invalid JSON.
Formatting versus validating versus minifying
Format when humans need to read it
Indentation and line breaks make nested payloads easier to scan, compare and review in tickets, logs or API responses.
Validate before using the data
A successful parse confirms syntactic JSON validity. It does not confirm that the fields match your application's schema or business rules.
Minify when whitespace is unnecessary
Compact JSON can reduce file size slightly for storage or transfer, though normal HTTP compression often has a much larger effect on network payload size.
Use stats to understand structure
Object, array, key and depth counts provide a quick sense of payload complexity after the JSON has parsed successfully.
Privacy and file handling
Formatting, validation, minification, copying and statistics run in browser JavaScript; the JSON content is not sent to a Smart Web Utility API. The file picker reads the selected file locally and accepts files up to 5 MB in the current implementation.
What JSON validation does not check
Syntax validation only confirms that the input is valid JSON. It does not verify a JSON Schema, API contract, required fields, data types expected by your application, semantic correctness or whether URLs, IDs and values inside the document are real.
Related developer tools
Frequently asked JSON questions
Does this JSON formatter upload my data?
No. The formatter and validator run locally in your browser. Network requests are not required to parse or format the JSON you paste into the editor.
Why is a JavaScript object not always valid JSON?
JSON has stricter syntax. For example, keys and strings must use double quotes, and JSON does not support functions, comments or undefined.
Does minifying JSON change its values?
The tool parses the JSON and serializes the resulting data without indentation. For valid JSON data, formatting whitespace is removed while the represented values and structure are preserved.
Can the validator check a JSON Schema?
No. This page checks JSON syntax, not a schema definition. Schema validation would require rules describing the expected structure, types and constraints.
How large a JSON file can I open?
The current file picker accepts JSON files smaller than 5 MB. Very large payloads are better handled with developer tooling designed for streaming or large-file processing.