Web Tools

JSON Formatter & Validator

Beautify, validate and minify JSON with syntax highlighting and precise error locations. Parsed by your browser's native engine, so even large payloads render instantly.

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Result

Formatted, syntax-highlighted output appears here after you press Format or Minify.

How to validate JSON syntax: developer how-to guide

Malformed JSON breaks APIs, CI pipelines and config loaders. This validator uses the browser's native JSON parser, so the verdict matches exactly what your application will see at runtime.

  1. Step 01

    Paste the JSON payload

    Drop in an API response, package manifest or configuration file. Validation is live — no button press needed for the verdict.

  2. Step 02

    Read the validation banner

    Green means the document parses cleanly. Red shows the parser message with the line and column of the first syntax error.

  3. Step 03

    Format for readability

    Press Format & Validate to re-indent with two spaces and colour-code keys, strings, numbers, booleans and nulls.

  4. Step 04

    Minify before shipping

    Press Minify to strip whitespace for smaller responses, then copy the result straight into your code or request body.

Frequently asked questions

How to validate JSON syntax?

Paste your JSON into the editor above. Validation runs on every keystroke: a green banner confirms valid syntax, while an error banner reports the parser message plus the exact line and column of the first problem.

What are the most common JSON errors?

Trailing commas, single quotes instead of double quotes, unquoted object keys, missing closing brackets, and comments — JSON has no comment syntax. The error line reported above points you straight to the offending character.

What does minifying JSON do?

Minify removes every unnecessary space and newline, producing the smallest valid payload. That reduces bandwidth for API responses and config files without changing the data.

Is it safe to paste production JSON here?

Yes. Parsing, formatting, highlighting and minifying all happen in your browser with native JavaScript. Nothing is uploaded, so API payloads and tokens never leave your machine.

Which indentation should I use when formatting?

Format & Validate uses two spaces, the dominant convention for JSON in web projects and the default of most linters and formatters.