JSON Formatter and Validator

Work through the input

1. Paste a complete JSON value into the input. A document may begin with an object, array, string, number, boolean, or null. Objects and arrays are common for APIs, but the JSON grammar permits all of these roots. Blank input is rejected instead of being mistaken for an empty object.
2. Format parses the entire document before printing it. That matters because a text replacement tool can add line breaks to invalid data and make it look trustworthy. Here, no formatted output is produced unless the browser successfully constructs the value. Choose two spaces for compact code reviews or four spaces when wider indentation makes a deeply nested payload easier to scan.
3. Validate uses the same strict parser and reports the root type, key count, primitive value count, and maximum nesting depth. Object keys are counted wherever they appear. Array positions are not keys, while strings, numbers, booleans, and null values count as leaf values. These diagnostics do not change the input and are intended as a quick shape check rather than a schema test.
4. Minify removes insignificant whitespace by parsing and serializing the value again. Spaces inside quoted strings are data and remain untouched. The operation can reduce a configuration snippet or request body, but it does not compress the text with gzip and it does not reorder object properties.
5. Copy places the processed result on the local clipboard, while Download JSON creates a temporary file directly in the browser. The page accepts up to two million characters to keep editing and parsing predictable on ordinary phones and laptops. Larger datasets are better handled with a streaming command-line parser rather than a browser textarea.

When json formatter and validator is useful

Check the output

• Valid JSON is not automatically valid for your application. A payload can be syntactically perfect while missing a required property, using a string where an integer is expected, or carrying an unsupported enum value. Contract validation requires a JSON Schema, TypeScript validator, or the receiving application's own rules.
• Comments, trailing commas, single-quoted strings, unquoted keys, NaN, and Infinity are not part of standard JSON. They may work in JavaScript source, JSON5, or a particular configuration system, but this strict validator rejects them because an ordinary JSON API would reject them too.
• Parsing and re-serializing can expose assumptions about very large numbers. JavaScript represents ordinary JSON numbers as IEEE-754 doubles, so integers beyond Number.MAX_SAFE_INTEGER may lose precision before serialization. Store identifiers and arbitrary-precision amounts as quoted strings when every digit must survive.
• Formatting does not redact secrets. API keys, tokens, customer records, and internal URLs remain visible in the output and clipboard. Local processing removes the formatter server from the risk, but anyone with access to the device, clipboard history, screen recording, or downloaded file may still see the data.

Questions about JSON Formatter and Validator

Related tools