Parse and format JSON from a pasted snippet or a dragged-and-dropped file, with live validation and structural stats.
Key Features of JSON Parser
- File Upload & Drag-and-Drop Drag and drop any .json file or select it from your device. The tool parses it locally in your browser.
- Real-Time Validation Find syntax errors immediately with clear error messages pointing to the problem line.
- Structural Insights See live key count, nesting depth, and byte size as you work.
- Syntax Highlighting Light and dark themes with GitHub-style colors using the Monaco editor.
- Custom Indentation Format with 2 or 4 spaces, or minify the code.
- One-Click Export Copy the result to your clipboard or download it as a formatted file.
- Auto-Repair Fix common errors like single quotes, trailing commas, unquoted keys, Python literals, and comments automatically.
JSON Parser Examples
Parsing an API Response File
Drop an API response file to check its keys, nesting depth, and size.
Input
{"user":{"id":101,"name":"Alice","roles":["admin","editor"]},"status":"active"}Output
{
"user": {
"id": 101,
"name": "Alice",
"roles": [
"admin",
"editor"
]
},
"status": "active"
}Auto-fixing Python-Style Dicts
Paste a Python dict with single quotes, True, False, or None. The tool converts them to valid JSON automatically.
Input
{'user': {'id': 101, 'active': True, 'role': None, 'verified': False}}Output
{
"user": {
"id": 101,
"active": true,
"role": null,
"verified": false
}
}How to Use JSON Parser
-
1. Paste or Upload JSON
Paste your raw code or drop a .json file.
-
2. Choose Indentation
Pick 2 spaces, 4 spaces, or Minified.
-
3. Inspect & Export
Check the formatted result and stats, then copy or download the file.
Common Use Cases for JSON Parser
- Inspecting Downloaded API Payloads Format and read API responses without opening an IDE.
- Validating Config Files Verify that package.json or settings.json files parse correctly.
- Debugging Nested Structures Spot overly nested configuration or data structures instantly.
- Converting Python Dicts to JSON Convert Python dicts to JSON without manual editing.
- Salvaging Broken or Hand-Edited JSON Clean up hand-written JSON that has trailing commas or unquoted keys.
The Technical Details
This tool parses JSON directly in the browser using the native JSON.parse method. It formats the output with JSON.stringify using the selected spacing.
File uploads use the browser’s FileReader API to read contents as UTF-8 text before parsing. The output panel uses Monaco Editor with its built-in JSON worker to handle syntax highlighting.
To calculate key count and maximum depth, the tool recursively traverses the parsed object tree once. This recursive run completes in linear time relative to the total number of items.
If native parsing fails, the repair pipeline steps in. It cleans line endings, replaces Python boolean and null literals, strips JS/Python/shell comments, drops trailing commas, and quotes bare keys using regular expressions. For single quotes, a character-by-character state machine runs to swap single quotes to double quotes while correctly preserving escaped quotes and existing double quotes inside strings. The status bar displays which repairs were made.
Frequently Asked Questions
What file types can I upload?
The file picker looks for .json files and reads them as UTF-8 text. If your file has another extension but contains valid JSON, you can still paste its contents into the input area.
Is my data kept private?
Yes. All reading, parsing, and formatting happen locally in your web browser. No data leaves your machine.
Why does it show key count instead of total values?
Counting object keys is usually the most helpful way to gauge an API schema's complexity. If you have arrays, their complexity will show up in the nesting depth instead.
Can I use this offline?
Yes. Once the page is loaded, the parser works completely offline. The Monaco editor is loaded from a CDN on your first visit and cached by your browser for offline use.
What happens if I drop a non-JSON file?
The tool reads the file as text and tries to parse it. If the parsing fails, you will see the exact syntax error message.
Can it handle Python-style dicts?
Yes. It automatically translates Python booleans (True/False to true/false), None to null, and swaps single quotes to double quotes. The status bar will list the exact changes made.
What kinds of broken JSON can it fix?
It fixes trailing commas before closing braces, unquoted object keys, single quotes, Python literals, and comments (JavaScript-style // and block comments, as well as Python # comments).