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JSON Formatter & Validator
Paste any JSON to instantly format it with readable indentation or minify it to one line. Syntax errors show the exact line and column. 100% in-browser — nothing leaves your device.
JSON.parse() + JSON.stringify(). Your data is never uploaded or stored.
About JSON Formatter & Validator
JSON Formatter & Validator is a free browser-based tool that lets you clean up raw, minified, or poorly indented JSON in seconds. Paste an API response, a config file snippet, or a log payload and click Format — the output is formatted with 2-space indentation so every nested object and array is easy to read. The same tool validates your JSON as it formats: if the input is not valid JSON, you see a clear error message with the line number and column so you can jump straight to the problem without guessing.
Need the smallest possible string? Toggle to Minify to strip all whitespace and newlines. Minified JSON is ideal for environment variables, HTTP request bodies, or any place where file size or token count matters. A Copy button puts the result on your clipboard in one click.
Common use cases
- Format a raw API response so you can read nested fields without straining.
- Validate a JSON config file before committing or deploying it.
- Minify a large JSON object to fit into an environment variable or request body.
- Debug a JSON parse error with an exact line and column location.
- Quickly check whether a string returned by a service is valid JSON.
Frequently asked questions
Is JSON Formatter & Validator free?
Yes. The tool is completely free with no account, no upload limit, and no rate limiting. All processing runs in your browser — no data is sent to any server.
Does the tool send my JSON to a server?
No. JSON formatting and validation use only your browser's built-in JSON.parse() and JSON.stringify() functions. Your JSON never leaves your device.
What counts as valid JSON?
Valid JSON follows RFC 8259. Strings must be double-quoted, keys in objects must be double-quoted strings, trailing commas are not allowed, and special characters must be escaped. JavaScript-style comments, single quotes, and unquoted keys are not valid JSON.
What is the difference between pretty-print and minified JSON?
Pretty-print formats JSON with 2-space indentation and newlines, making it easy to read. Minified JSON removes all whitespace and newlines, producing the smallest possible string — useful for APIs and storage where bandwidth or file size matters.
Why does the error message show a line and column number?
When JSON.parse() fails, this tool calculates the exact line and column of the syntax error so you can jump straight to the problem in your editor rather than scanning the entire document.