Free JSON Formatter & Validator
Beautify, validate, and minify JSON right in your browser. Errors are pinpointed by line and column — nothing is uploaded, your data stays on your device.
Your JSON is parsed entirely in your browser — nothing is uploaded.
How to Format JSON in Your Browser
Paste your JSON
Drop in raw, minified, or messy JSON — an API response, a config file, a log line. There's no size limit and nothing is uploaded.
Format, minify, or validate
Beautify it with 2-space, 4-space, or tab indentation, collapse it to a single line, or just check that it's valid. Errors are flagged by line and column.
Copy or download the result
Copy the output to your clipboard or download it as a .json file, ready to drop into your code, request, or config.
Everything You Need to Work With JSON
A good JSON tool does three jobs well — make it readable, make it small, and tell you exactly what's wrong. Here's how this one handles each.
Beautify with your indent
Turn a wall of minified JSON into a clean, indented tree. Choose 2 spaces, 4 spaces, or tabs to match your project's style.
Minify to one line
Strip every space and newline to get the smallest valid JSON — handy for embedding in a URL, a config value, or a request body.
Precise error location
Invalid JSON is reported with the exact line and column of the problem, so you find the stray comma or missing quote in seconds.
Private and instant
Parsing runs entirely in your browser with the native JSON engine. Your payloads — which often contain tokens or personal data — never leave your device.
When a JSON Formatter Helps
JSON is everywhere in modern development. These are the moments you reach for a formatter.
Read an API response
Paste a raw, minified API payload and beautify it to actually see the structure — nested objects, arrays, and all the fields at a glance.
Debug invalid JSON
When a parser rejects your JSON, paste it here to get the exact line and column of the syntax error instead of a vague 'unexpected token'.
Clean up config files
Reformat a hand-edited package.json, tsconfig, or settings file so the indentation is consistent before you commit it.
Shrink JSON for embedding
Minify a JSON blob before pasting it into an environment variable, a query string, or an inline script where whitespace is wasted bytes.
Format JSON Without Uploading Your Payloads
Many online JSON formatters send your input to a server to process it. Since JSON payloads routinely carry API keys, tokens, and user data, doing it locally is the safer default.
In-browser with SupaTools
- Your JSON is parsed on your device, never uploaded
- Format, minify, and validate in one place
- Errors pinpointed by line and column
- Free with no sign-up and no size limit
Typical server-side formatters
- Your payload — tokens and all — sent to their server
- Unclear how long the input is logged or retained
- Often just beautify, with vague error messages
- Ads or rate limits on larger inputs
Pro Tips for Working With JSON
Watch for trailing commas
Strict JSON forbids a comma after the last item in an object or array — a common cause of parse errors that this validator flags by position.
Use double quotes, always
JSON keys and strings must use double quotes, not single quotes. Config pasted from JavaScript often trips on this.
Minify for transport, beautify for reading
Keep a minified copy for embedding and sending over the wire, and a beautified copy for review — both come from the same source here.
JSON Formatter — Frequently Asked Questions
Format Your JSON Free — No Sign-Up
Paste your JSON above to beautify, minify, or validate it instantly. Nothing is uploaded — it all runs in your browser.