JSON Formatter & Validator
Paste JSON to instantly beautify, validate, or minify it. The JSON formatter re-indents your document, flags syntax errors with the exact line and column, and never uploads anything — it all runs in your browser.
Beautify, validate, or minify JSON — all in one place
JSON (JavaScript Object Notation) is the most common format for API responses, configuration files, and data exchange between systems. It is strict: every key and string must use double quotes, commas separate items but are never allowed after the last one, and comments are not permitted. A single misplaced character breaks the whole document, which is why a good formatter and validator saves so much debugging time.
How the error reporting works
When you click Format or Validate, the tool parses your text with the browser's native JSON engine. If parsing fails, it captures the character position of the failure and translates it into a human-friendly line and column so you can jump straight to the problem — no more scanning hundreds of lines by eye. When the JSON is valid, the editor is re-indented using the indent size you selected and the status turns green.
When to minify JSON
Minified JSON removes all non-essential whitespace, shrinking the payload for faster network transfers, smaller files, or pasting a compact object into source code and API clients. Because whitespace is not significant in JSON, minifying and re-formatting are perfectly reversible — the data is identical either way. Everything here stays on your device, so it is safe for JSON that contains credentials or private data.
Frequently asked questions
How do I format (beautify) JSON?
Paste your JSON into the editor and click Format. The tool re-indents the whole document with the indent size you pick (2 spaces, 4 spaces, or tabs) so nested objects and arrays are easy to read. If the JSON is invalid it will tell you exactly where the problem is instead of silently reformatting.
What does the JSON validator check?
It runs your text through a strict JSON parser and reports the first syntax error it finds — a trailing comma, a missing quote, an unclosed bracket, a single-quoted string, and so on — along with the line and column where it occurs. Valid JSON is confirmed with a green status message.
How is minifying different from formatting?
Minifying strips every space and line break, producing the smallest valid JSON on a single line — useful for embedding in code, reducing payload size, or copying into an API request. Formatting does the opposite: it adds indentation and line breaks for human readability. Both produce equivalent JSON.
Is my JSON uploaded to a server?
No. Everything happens locally in your browser using the built-in JSON parser — your data never leaves your device and nothing is logged. That makes it safe to paste sensitive API responses, tokens, or configuration you would not want to send to a third-party website.
Why does my JSON say invalid when it looks fine?
The most common causes are trailing commas after the last item in an object or array, comments (JSON does not allow // or /* */), single quotes instead of double quotes, unquoted keys, or a stray character copied from a rich-text source. The error line and column point you to the exact spot to fix.
Can I convert the formatted JSON to another format?
Yes — once your JSON is valid, use our JSON to CSV converter to turn an array of objects into a spreadsheet-ready CSV file, also entirely in your browser.