JSON Formatter
Format, validate and beautify JSON instantly with syntax highlighting.
Paste minified or messy JSON to get clean, consistently indented output — nested objects and arrays become readable at a glance.
Choose 2-space or 4-space indentation for reading and debugging, or minified output for shipping smaller payloads. Invalid JSON returns the exact parser error instead of formatted output.
How it works
Malformed JSON is one of the most common causes of broken API integrations, and the error messages browsers and languages give you are often unhelpful -- a vague "unexpected token" with no context. This formatter parses your raw JSON, and if it's valid, re-serializes it with clean, consistent indentation so nested objects and arrays are actually readable.
If the JSON is invalid, you get the exact parser error rather than a guess, so you can find the missing comma or unclosed bracket quickly. Choose 2-space, 4-space, or fully minified output depending on whether you're reading the JSON yourself or shipping it over the wire.
Everything runs in your browser using the native JSON.parse/stringify, so nothing you paste in is ever sent to a server -- safe to use even with real API responses or config files you'd rather not upload anywhere.
Worked example
Formatting {“name”:“AlfennAI”,“tools”:37,“active”:true} with 2-space indentation produces each key on its own line, nested two spaces in; with the minified option the same document collapses to a single compact line for transport.
Formatting is not validation: if the input cannot be parsed, nothing is reformatted — run it through the JSON validator to pinpoint the syntax error first.
Formatted versus minified
Use formatted output (2 or 4 spaces, up to 8) when a human needs to read or diff the document. Use minified output (indent 0) when a machine consumes it and every byte counts, such as API request bodies or embedded configs.
Privacy
Everything runs locally with the browser's native JSON.parse and JSON.stringify. Nothing pasted here is sent to a server, stored, or logged — but avoid pasting live secrets or credentials into any web tool as a general habit.
Frequently asked questions
What is JSON formatting?
JSON formatting (pretty-printing) re-serializes compact JSON with consistent indentation and line breaks, so nested objects, arrays, strings and numbers are easy to scan when debugging APIs or configs.
Does this tool store or send my JSON anywhere?
No. Formatting happens entirely in your browser with the native JSON parser; your data never leaves your device, so real API responses are safe to paste.
What happens if my JSON is invalid?
You'll see the exact parser error, including the position of the problem, so you can fix it fast — for example a trailing comma reports the position where the parser expected the next value.
Can I minify JSON instead of formatting it?
Yes -- set indent to 0 ("Minified" option) to collapse the JSON to a single compact line, useful for reducing payload size before sending over a network.
Can I format nested JSON?
Yes — objects and arrays nested to any depth are indented level by level, which is exactly where manual reading of minified payloads breaks down.
What's the difference between formatting and validating?
Formatting re-serializes valid JSON with consistent indentation. Validating just checks whether the syntax is correct without changing anything -- use the dedicated JSON Validator if you only need a yes/no check.