JSON Formatter & Validator
Format, validate, and visualize JSON data online. Syntax highlighting, tree view, error detection, JSONC support, auto-fix, and minification. Free, real-time, 100% browser-based.
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What is JSON?
JSON (JavaScript Object Notation) is a lightweight, human-readable data format used to exchange data between servers, APIs, and applications. It supports six data types: strings, numbers, booleans, null, objects (key-value pairs), and arrays (ordered lists).
JSON has become the de facto standard for web APIs, configuration files, NoSQL databases, and cross-platform data exchange. Its simplicity and universal support in every programming language make it ideal for both human and machine consumption.
JSON vs XML Comparison
| Feature | JSON | XML |
|---|---|---|
| Syntax | Lightweight, minimal punctuation | Verbose, tag-based markup |
| Data Types | Strings, numbers, booleans, null, objects, arrays | All values are strings by default |
| Comments | Not supported (JSONC extension adds them) | Supported natively |
| Parsing | JSON.parse() — built into every language | Requires XML parser library |
| File Size | 30–50% smaller than equivalent XML | Larger due to opening/closing tags |
| APIs | Dominant in REST APIs and web services | Common in SOAP and legacy enterprise systems |
How to Use — 3 Simple Steps
Enter Your JSON
Paste your JSON into the input area, or upload / drag & drop a .json file. The tool supports standard JSON, JSONC (with comments), and even malformed JSON with the auto-fix option.
Choose Your Mode
Select Format to beautify with indentation, Unminify to expand compressed JSON into readable format, or Minify to compress into a single line. Toggle options like sort keys, remove comments, or auto-fix as needed.
Explore & Export
Switch to Tree View to explore the JSON structure interactively. Click any value to see its JSON path. Copy the result to clipboard or download as a .json file.
Common JSON Errors
| Error | Example | Fix |
|---|---|---|
| Trailing comma | {"a": 1, "b": 2,} |
Remove comma after last item |
| Single quotes | {'name': 'John'} |
Use double quotes for strings |
| Unquoted keys | {name: "John"} |
Wrap keys in double quotes |
| Comments | // comment
{"a": 1} |
Remove comments or use JSONC mode |
| Missing quotes on value | {"name": John} |
Wrap string values in double quotes |
Enable the “Auto-fix common errors” option to automatically repair these issues before formatting.
Explore with Tree View
Switch to Tree View for large JSON documents. Click any node to expand/collapse, and click values to see the exact JSON path for use in your code.
VS Code Settings (JSONC)
Working with settings.json or tsconfig.json? Enable “Remove comments” to strip // and /* */ comments before validation.
Sort for Diff-Friendly Output
Enable “Sort keys” before committing JSON to version control. Alphabetical keys produce cleaner git diffs and reduce merge conflicts.
Minify for Production
Use Minify mode to compress JSON before embedding in APIs or config files. Removing whitespace can reduce file size by 30–50% for large documents.
Frequently Asked Questions
What is JSON and why does it need formatting?
JSON (JavaScript Object Notation) is a lightweight data-interchange format used by APIs, config files, and databases. Raw or minified JSON is often a single long line that is difficult to read. A JSON formatter adds proper indentation and line breaks, making the structure clear and easy to understand.
What is the difference between JSON and JSONC?
JSONC (JSON with Comments) allows single-line (//) and multi-line (/* */) comments inside JSON. Standard JSON does not support comments. This tool can strip comments from JSONC input before parsing, making it compatible with VS Code settings, tsconfig.json, and other JSONC files.
How does the auto-fix feature work?
The auto-fix feature attempts to repair common JSON errors: it removes trailing commas after the last item in arrays and objects, converts single quotes to double quotes, adds quotes around unquoted keys, and handles other typical mistakes. This helps when pasting JSON from logs, code snippets, or hand-written input.
What is a JSON path?
A JSON path is a dot-notation string that describes the location of a specific value in a JSON document. For example, $.users[0].name refers to the name property of the first user in a users array. This tool shows the JSON path when you click any value in the tree view.
Is my data safe when using this tool?
Yes, completely safe. All JSON formatting, validation, and processing happens entirely in your browser using JavaScript. Your data is never sent to any server. You can verify this by checking the Network tab in your browser developer tools.