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JSON Formatter & Validator
Paste raw JSON and get clean, indented, validated output in one click.
Turn unreadable JSON into something you can actually work with
JSON is easy for machines to parse and painful for humans to read. A single-line API response with nested objects, escaped quotes and arrays of arrays can run to thousands of characters with no line breaks at all. This JSON formatter takes that wall of text and rewrites it with consistent indentation, one key per line, so you can see the structure at a glance instead of counting brackets.
It also validates while it formats. If a comma is missing, a quote is unbalanced or a trailing comma slipped in from a JavaScript object literal, the tool tells you instead of silently producing broken output. Everything is processed on our server and returned to you, without storing your payload once formatting is complete.
How to format JSON online
- Copy the JSON you want to clean up. It can be a full API response, a config file, a log line or a fragment.
- Paste it into the input box above.
- Choose your indentation if the tool offers it — two spaces is the common default, four is easier to read on deeply nested data.
- Press the format button. Valid JSON is re-indented immediately; invalid JSON returns an error pointing at the problem.
- Copy the formatted result, or use the minify option to collapse it back into a single compact line before shipping it.
What this JSON tool does
- Pretty-printing — rewrites your JSON with consistent indentation and line breaks so nesting is obvious.
- Syntax validation — catches missing commas, unbalanced brackets, single quotes and trailing commas before they reach production.
- Minification — strips every unnecessary space and newline when you need the smallest possible payload.
- Unicode safe — handles escaped sequences and non-Latin characters without mangling them.
- Server-side processing — your data is processed on the server and not stored, which matters when the JSON contains tokens, customer records or internal IDs.
- No limits or accounts — paste as often as you like; there is nothing to install and nothing to sign up for.
When you would reach for it
- Debugging an API response that arrives as one enormous unbroken line.
- Checking a
package.json,composer.jsonor CI config before committing it. - Reviewing a webhook payload that a third-party service sent you.
- Cleaning up JSON copied out of browser devtools or a log aggregator.
- Minifying a configuration blob so it fits inside an environment variable.
JSON formatting questions
Is my JSON uploaded to a server?
Yes. Your JSON is sent to the server for formatting and validation, but the content is processed and immediately discarded without being stored. See our privacy policy for details.
What is the difference between formatting and validating?
Formatting changes only the whitespace — indentation and line breaks — so the data is easier to read. Validating checks that the text is legal JSON in the first place. This tool does both: it can only format what it can successfully parse.
Why does my JSON fail validation when it works in JavaScript?
JavaScript object literals are more forgiving than JSON. JSON requires double quotes around every key and string, forbids trailing commas, and does not allow comments or single quotes. Those are the three mistakes that cause almost every validation failure.
Can it handle very large files?
It handles files up to the limits of your browser’s memory, which in practice means several megabytes without trouble. Extremely large exports are better processed with a command-line tool such as jq.
Does formatting change my data?
No. Only whitespace changes. Keys, values, ordering and types are preserved exactly, so the formatted output parses to the same object as the original.
