JSON Formatter & Validator
/json-formatterFormat, validate, and minify JSON data. Pretty-print or compress JSON instantly in your browser.
Minified JSON from APIs and logs is nearly impossible to read, and a single missing comma can break an entire config file. This tool pretty-prints JSON with proper indentation and flags syntax errors immediately. You can also minify it back down for storage or debugging. Both input and output stay in your browser.
A 200 response your code cannot parse is a debugging session waiting to happen. Paste the body into the formatter, and the indented structure shows whether the data is nested under an unexpected key, wrapped in an envelope you forgot to unwrap, or an array when you expected an object. Format before you write the parser. It also catches a response that is not valid JSON at all, which happens when a proxy returns an HTML error page instead of data. The validation step saves a misleading round of debugging.
Moving a config between environments, or committing one to a repo, is safer after you have validated it. Run the file through the formatter and check for trailing commas, duplicate keys, or single-quoted strings, all of which pass in some parsers and break others. If you paste JSON into code, formatting it first surfaces these errors before a failed request or build. Use minify when you need a compact payload for storage or transfer, and format again to compare two versions side by side. The file never leaves your browser.
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FAQ
Frequently asked questions
Everything you need to know about json formatter & validator.
What does this JSON tool do?
It validates JSON with a full parse, pretty-prints with 2, 4, or 8 space indentation or tabs, optionally sorts object keys alphabetically, and can emit minified single-line output.
Is my data sent to a server?
No. Parsing and formatting run entirely in your browser using native JSON.parse and JSON.stringify. Nothing is transmitted.
Why do I get a JSON parse error?
Trailing commas, single quotes, unquoted keys, and comments are not valid JSON. Remove or fix them, then run Format again. The parser error message points at the problem.
Can it handle very large JSON documents?
Yes, but everything is parsed synchronously, so very large documents may make the page feel slow for a moment. Smaller documents format instantly.
How do I use tab indentation?
Enable the Use tabs instead of spaces toggle. When tabs are active the space-size selector is disabled, since indentation is fixed to tab characters.
Does sorting keys affect arrays?
No. The sort replacer only reorders the keys of plain objects, including nested ones; array order is always preserved.
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