JSON Formatter & Validator

JSON (JavaScript Object Notation) is the universal data exchange format for APIs, configuration files, database records, and inter-service communication. Minified JSON, stripped of all whitespace, is efficient for transmission but impossible to read. Formatted JSON with proper indentation is readable but verbose. This tool lets you move between both directions instantly: paste compressed API responses to read them clearly, or minify formatted config files before committing them to production. The validator also pinpoints syntax errors with line and column numbers so you can fix malformed JSON quickly.

How to use

1. Paste your JSON. Drop your JSON string into the input area. It can be formatted or minified, complete or partial. The tool handles both with no preprocessing required.
2. Format or minify. Click Format/Prettify to add indentation and line breaks, making nested structures visually clear. Click Minify to strip all whitespace and produce the most compact possible JSON string for production use or size-limited transmission.
3. Review validation results. If your JSON contains a syntax error, the tool reports the exact line and character position of the problem. Common errors include trailing commas (not valid in JSON), single-quoted strings (JSON requires double quotes), and unescaped special characters in strings.
4. Copy the output. Click Copy to copy the formatted or minified JSON to your clipboard. Paste it wherever you need it, a code editor, API client, config file, or documentation.

Tips for best results

• Fix validation errors before formatting. Formatting invalid JSON produces confusing output. If validation reports an error, fix the syntax issue first, then reformat. The error message includes the exact line and character where JSON parsing failed.
• Use for API debugging. When debugging API responses, paste the raw response body here to get an indented, readable view of the data structure. This is much faster than mentally parsing a minified JSON blob from network DevTools.
• Compare two JSON objects with text diff. To see what changed between two API response versions, format both, then paste them into the text diff tool side by side to see exactly which fields changed.
• Use for config file validation. JSON is the base format for many config files (package.json, tsconfig.json, .eslintrc). Paste a config here to catch syntax errors before committing a broken config to your repo.

Why use PixMidas

• Instant validation with error details. The formatter reports exactly where a JSON syntax error occurred, including line number and character position, so you can find and fix the problem immediately.
• 100% private. All JSON processing runs on your device using JavaScript's native JSON.parse() and JSON.stringify() functions. Your data never leaves your device.
• No account needed. Free and instant. JSON processing runs locally on your device.

Frequently asked questions

What is the difference between JSON format and minification?

Formatted JSON uses indentation (typically 2 or 4 spaces) and line breaks to present the data structure visually, each key-value pair on its own line, nested objects indented. Minified JSON removes all whitespace that isn't inside string values, producing the most compact representation. Both represent exactly the same data. Use formatted JSON for development, config files, and documentation. Use minified JSON for production API responses, localStorage payloads, and anywhere network transfer size matters.

Why is my JSON invalid even though it looks correct?

The most common causes of JSON validation errors: trailing commas after the last item in an object or array (e.g., {"a": 1,}, invalid in JSON, valid in JavaScript); single-quoted strings (JSON requires double quotes around all strings and keys); unescaped backslashes or special characters in string values; missing commas between items; and comments (JSON does not support comments, use JSONC or JSON5 formats if you need comments in config files).

What is the difference between JSON and JavaScript objects?

JavaScript object literals allow unquoted keys, single-quoted strings, trailing commas, and comments. JSON requires double-quoted strings for all keys and values, no trailing commas, and no comments. JSON is a strict subset of JavaScript's data notation that is language-independent. This is why JavaScript code that looks like valid JSON often contains subtle differences that make it technically invalid JSON.

How do I format JSON in a code editor?

Most code editors have built-in JSON formatting. In VS Code: open the JSON file, press Shift+Alt+F (Windows/Linux) or Shift+Option+F (Mac). In JetBrains IDEs: Ctrl+Alt+L. For one-off formatting of JSON from API responses or clipboard content, this online tool is faster than opening a file in a code editor.

Can I use this to validate JSON Schema files?

This tool validates that your JSON is syntactically correct JSON, it checks structure and syntax. It does not validate JSON against a JSON Schema specification (which would check that the data matches an expected shape defined in a schema document). For JSON Schema validation, use a dedicated JSON Schema validator library or tool.

What is JSONC and why does it fail validation here?

JSONC (JSON with Comments) is a superset of JSON that allows // single-line and /* multi-line */ comments. It's used in VS Code configuration files (settings.json, tsconfig.json) and some other developer tools. Standard JSON parsers reject comments. If you're working with JSONC files, remove the comments before pasting here, or use an editor that understands JSONC natively.