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JSON Formatter

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Output

Online JSON formatter / minifier / validator. Processed locally in the browser — data never leaves your device.

How to Use & FAQ5 steps · 8 Q&A

JSON Formatter

Online JSON formatter / minifier / validator. Processed locally in the browser — data never leaves your device.

How to Use

  1. Paste JSON textPaste the JSON you want to process into the input box; whole API responses copied from a client are supported.
  2. Choose Format or MinifyChoose to beautify with indentation (for reading) or minify to a single line (for transmission).
  3. Check the validation resultIf there is a syntax error, the tool flags the location so you can fix it quickly.
  4. Copy the resultCopy the processed JSON with one click; mind the copy format if quotes are expected.
  5. Tips for very large textFor very large JSON, validate the structure on a small sample first, then process the whole thing, to avoid using too much memory at once.

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FAQ

What is JSON formatting used for?

It indents and beautifies minified or messy JSON for readability, while validating syntax errors and locating problems during parsing. It is especially handy when debugging API responses or inspecting config files.

Does the tool upload my JSON data?

No. Formatting and validation happen entirely in the browser — data is never uploaded to a server, so you can safely paste JSON containing internal fields without leaking it.

How do I minify JSON to one line?

Use the "Minify" function to strip extra whitespace and newlines, producing single-line JSON suitable for transmission or storage. It is smaller but less readable, often used in build output before deployment.

How do I locate a JSON parse error?

The tool points to the error location (line/column). Common causes are a trailing comma, mismatched quotes, or single quotes — JSON only allows double quotes for keys and strings, and no trailing comma is allowed.

Does JSON support comments?

Standard JSON does not support comments. If you really need them, use a superset such as JSON5 / JSONC, but generic parsers and APIs usually cannot read them. In production, move notes to separate docs or fields.

Will very large JSON be slow?

Processing happens locally in the browser; very large text may briefly use more memory and take longer. Up to a few MB is usually smooth; for very large files, process in parts or use a streaming parser.

Does formatting change the data content?

No. Formatting only adjusts whitespace and indentation; it does not change keys, string values or numbers. Compression also removes whitespace without affecting meaning. Note: duplicate keys in an object are usually resolved to the last one when parsed.

Will large integers (e.g. order IDs) lose precision?

Yes. JavaScript numbers are only precise up to about 2^53, so integers beyond that range (e.g. 19-digit order IDs) can become inaccurate after parsing. Keep such values as strings for exactness; this tool tries to present them verbatim.