Format, validate, and minify JSON in your browser.
Minified JSON from an API response or a log line is nearly impossible to read, and a single missing comma can break a config file in a way that takes far too long to spot. This free JSON formatter and validator pretty-prints any JSON document with two-space indentation, flags syntax errors with the line number where parsing failed, and can also minify JSON back down for production payloads or sort object keys alphabetically so two documents are easier to compare.
Everything happens locally. The tool parses your input with the browser’s native JSON engine, so nothing you paste is uploaded to a server — a real consideration when the JSON you are debugging contains API keys, customer records, or internal URLs. Validation runs as you type: a green Valid JSON badge appears when the document parses, along with a character and byte count that is handy when you are watching payload sizes.
Use it as a quick JSON beautifier before a code review, a JSON validator when an API rejects your request body, or a minifier when you want to shave bytes off a response fixture. When you are done, copy the result to your clipboard or download it as a .json file.
Drop the raw JSON into the input box on the left. The tool parses it instantly as you type or paste.
Choose Pretty for indented, readable output, Minify to strip all whitespace, or Sort keys to alphabetize every object key recursively.
A Valid JSON badge with character and byte counts confirms the document parses. If it is invalid, the exact parser error and line number appear instead.
Use the Copy button to put the formatted JSON on your clipboard, or Download to save it as a data.json file.
Yes. The JSON is parsed and formatted entirely in your browser using the native JSON engine, and nothing you paste is sent to any server.
Paste the document and the tool shows the parser’s error message along with the line number where parsing failed, so you can jump straight to the broken spot. Common culprits are trailing commas, single quotes, and unquoted keys.
Formatting (pretty-printing) adds indentation and line breaks so humans can read the structure. Minifying removes all unnecessary whitespace to make the document as small as possible for transmission or storage. Both produce semantically identical JSON.
Sorting keys alphabetically makes two JSON documents directly comparable in a diff tool, since key order in JSON objects carries no meaning. It is useful for comparing API responses, config files, or snapshot fixtures.
No. The JSON specification does not allow comments, trailing commas, or single-quoted strings. If your file uses them it may be JSON5 or JSONC, which this validator will correctly reject as standard JSON.
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