JSON Formatter

Beautify and structure your JSON data with custom indentation

0Bytes

Indentation Level:

Format JSON for humans and for version control

Formatting JSON is about consistency: the same indentation every time, one property per line, arrays and objects clearly nested. That is what makes a config file pleasant to review in a pull request or an API sample easy to scan in documentation. Paste your data here, choose the indentation you prefer and the formatter returns tidy text that can go straight back into your project.

How to format

Put your JSON in the Input JSON field with typing, Paste, or Load Sample JSON, which creates a user profile with a timestamp. The Bytes figure in the header tracks input size.
Under Indentation Level, select 2 Spaces, 4 Spaces (the default) or Tabs.
Press Format & Beautify JSON.
In the Formatted Result panel, choose Copy JSON or Download .json, which saves formatted-json.json.

What you get

Syntax colouring on screen: keys, strings, numbers, booleans and null each have their own colour. The copied and downloaded text has no colour codes.
Built-in validation: if the input cannot be parsed, an error pop-up appears with the message, so a successful format also means the JSON was valid.
Normalised output: spacing, line breaks and spacing after colons are rewritten uniformly.

Typical uses

Standardising a settings file to 2-space indentation before committing it to a repository whose style guide requires it.
Pasting an API sample into a README or a support answer in readable form.
Finding a missing bracket, since a failed format points to a syntax problem.
Preparing a test fixture with a consistent layout for snapshot tests.

Details and edge cases

Formatting works by parsing the JSON and printing it again, so anything not in the JSON specification is refused: comments, trailing commas, single-quoted strings and unquoted property names all trigger an error. If your file is JSON with comments, such as some editor settings files, remove the comments first. Because the data is rebuilt, a repeated key appears only once with its last value, and property names that look like whole numbers may move to the top of an object, since JavaScript orders those first. Very long numbers can lose precision. The tool cannot repair broken JSON automatically; it only reports the first problem the parser meets. Everything is processed by JavaScript in the browser tab, so the practical size limit depends on your device.

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Frequently Asked Questions

Can this tool fix invalid JSON?

No. It formats only valid JSON. If parsing fails, a message from the browser's parser explains the first problem, such as an unexpected token, and you correct the input yourself before formatting again.

Will key order change after formatting?

Usually not, but property names that look like whole numbers, such as 10 or 2, may be moved to the front by JavaScript when the object is rebuilt. Other keys keep the order you gave them.

Are comments in JSON preserved?

Comments are not valid JSON, so they cause an error rather than being kept. If your file uses comments, delete them before formatting and add them back afterwards in your editor.

Which indentation should I choose?

Match your project's convention. Two spaces keeps deeply nested data narrower, four spaces is a common default, and tabs let each developer set their own display width. The output content is otherwise identical.

Is the download coloured like the on-screen result?

No. Colouring is only a display feature. Both Copy JSON and Download .json produce plain text that is safe to save, commit or send to an API, with no colour codes or markup mixed into the data.