Developer utility

JSON formatter & validator

Форматирование, минификация и проверка синтаксиса JSON — всё в браузере

Source JSON

Result

Formatted JSON will appear here

About working with JSON

Features

  • • Readable formatting with indentation
  • • Minify to a single line
  • • Syntax validation with the error message

Common mistakes

  • • Single quotes instead of double quotes
  • • A trailing comma in an array or object
  • • Unclosed brackets or quotes

Working with JSON without errors

Why format JSON

JSON is the main data-exchange format on the web: APIs, configurations, JSON-LD markup for SEO. Readable formatting helps you quickly find the fields you need and spot structural errors.

The validator saves time when debugging integrations: instead of catching a failure on the backend, you immediately see invalid syntax.

JSON and SEO

Schema.org structured data is most often placed in JSON-LD format. A syntax error causes the search engine to ignore all the markup, so it is worth checking with a formatter before publishing.

After formatting, check the markup itself with our structured-data checker and Google’s Rich Results Test.

Frequently asked questions

What does a JSON formatter do?+

It brings JSON to a readable form with indentation and line breaks, and can also compress it into one line (minification). At the same time it checks the syntax and shows exactly where the error is.

Is the data uploaded to a server?+

No. Parsing and formatting are done in the browser with the built-in JSON parser — the entered data is not sent anywhere, which matters when working with confidential API responses.

How do I find where the error is in the JSON?+

For invalid JSON the tool shows the parser message with the position — usually an extra or missing comma, the wrong type of quotes, or an unclosed bracket. A common cause is single quotes instead of double.

How is JSON minification useful?+

Compressed JSON without spaces and line breaks takes up less space and transfers faster — useful for API responses, configs and embedding structured data in HTML.