How to Format & Validate JSON
JSON is easy to produce but easy to break — one stray comma or missing quote and a whole payload fails to parse. This tool takes the guesswork out. Paste your JSON and it's parsed and re-rendered instantly: choose two-space, four-space or tab indentation to beautify it, or switch to minify to strip every unnecessary character down to the smallest valid form. If the JSON is well-formed you get a green confirmation along with the formatted and minified byte sizes; if it isn't, you get the exact line and column of the problem so you can fix it in seconds rather than hunting. Turn on Sort keys to alphabetise every object at every level — perfect for producing stable, diff-friendly files. Everything is computed in your browser, so even large or confidential payloads never leave your device. When it looks right, copy it or download a .json file.
Paste your JSON
Drop in messy, minified or hand-written JSON; it's parsed locally.
Pick your options
Choose indentation or minify, and optionally sort the keys.
Copy or download
Grab the clean result or save it as a .json file.
Beautify vs Minify
Beautify (pretty-print)
Adds indentation and line breaks so nested structure is easy to read and edit. Ideal while debugging, reviewing an API response, or committing config to version control.
Minify (compact)
Removes every unnecessary space and line break to shrink the payload. Ideal for sending over the network, embedding in code, or storing where size matters.
Common Use Cases
Debug API responses
Beautify a raw response to read its structure at a glance.
Fix broken JSON
Jump straight to the line and column of a syntax error.
Clean config files
Format and sort keys for tidy, consistent config.
Shrink payloads
Minify JSON before sending it over the wire.
Diff-friendly output
Sort keys so version-control diffs stay small and clear.
Learning & teaching
Show well-formatted JSON in docs and tutorials.
Copy-paste cleanup
Tidy JSON pasted from logs or chat messages.
Pre-commit checks
Validate JSON before committing or deploying it.
Tips & Best Practices
Read the error location
When JSON is invalid, the reported line and column point right at the problem — start there.
Watch for trailing commas
A comma after the last item is the most common error; JSON doesn't allow it.
Use double quotes
JSON requires double quotes around keys and strings — single quotes are invalid.
Sort keys for diffs
Alphabetising keys keeps version-control diffs minimal when data is re-saved.
Minify for transport
Ship minified JSON to save bandwidth, and beautify only when reading it.
Mind big numbers
Very large integers can lose precision in any JSON tool; keep them as strings if exactness matters.
Troubleshooting
It says my JSON is invalid
Check the reported line and column. The usual culprits are a trailing comma, a missing quote, or single quotes instead of double.
My comments were rejected
Standard JSON doesn't allow comments. Remove // or /* */ before formatting.
Keys aren't sorted
Enable the Sort keys option; it alphabetises objects at every level of nesting.
A big number changed
JSON parsers use floating point, so extremely large integers can lose precision. Store such values as strings.
Frequently Asked Questions
How do I format JSON for free?
Paste your JSON above and it's beautified instantly. Choose indentation or minify, then copy or download — free, no signup.
Does it validate my JSON?
Yes. It tells you live whether the JSON is valid, and if not, the exact line and column of the error.
Can it minify JSON?
Yes. Choose the Minify option to strip all whitespace down to the smallest valid JSON.
What indentation can I use?
Two spaces, four spaces or tabs — pick whichever matches your project's style.
Can it sort object keys?
Yes. Turn on Sort keys to alphabetise every object at every level for diff-friendly output.
Where is the error shown?
Invalid JSON reports the precise line and column, so you can fix the problem quickly.
Does it show the file size?
Yes. When valid, it shows both the formatted and minified byte sizes.
Does it allow comments?
Standard JSON doesn't allow comments, so remove them before formatting or the input won't parse.
Is my data sent to a server?
No. Everything happens inside your browser, so your data never leaves your device.
Can I download the result?
Yes. Save the output as a .json file, or copy it to your clipboard.
How large a file can it handle?
It comfortably formats large JSON documents, all within your browser.
Why did a large number change?
JSON uses floating-point numbers, so very large integers may lose precision. Keep them as strings if exactness matters.
Does it work offline?
Once the page has loaded it runs entirely in your browser, so it keeps working without a connection.
Can it fix my JSON automatically?
It points you to the exact error location, but you make the fix — that keeps your data accurate and intentional.
Does it preserve Unicode?
Yes. Any Unicode characters in your JSON are preserved in the output.
Can I convert JSON to other formats?
Yes — try our JSON to CSV, JSON to YAML and JSON to XML converters.
Does it work on phones?
Yes, in any modern browser on Windows, Mac, Android or iPhone with nothing to install.
Is this tool really free?
Completely free, forever — no account, no ads and no premium wall.
100% free · No signup · Processed in your browser · Data never sent
Last updated: August 2026 · FlipMyFormat JSON Formatter & Validator
Written and maintained by the FlipMyFormat team · Runs entirely in your browser