JSON Formatter, Validator & Tree Viewer
Beautify ugly or minified JSON data with 2-space or 4-space indentation. Pinpoints syntax errors with line and column markers. Includes one-click minification and tree view.
What is the JSON Formatter, Validator & Tree Viewer?
This tool validates, formats, and indents messy or minified JSON strings into clean, human-readable code with syntax highlighting, or minifies them for production.
Recursive Descent Lexing and RFC 8259 AST Construction
The parser converts the character stream into structural tokens (brackets, braces, colons, commas, strings, numbers, booleans, and null). It verifies grammar rules such as mandatory double-quoted keys, prohibits trailing commas, and constructs a memory representation. Serializing traverses the object hierarchy recursively, adding line breaks and indentation depth multipliers.
How to Use the JSON Formatter, Validator & Tree Viewer
Paste Your JSON
Paste your raw or minified JSON string into the editor, or load a sample.
Choose Formatting Options
Select 2-space indentation (standard for JavaScript/web), 4-space indentation, or minify to single-line.
Review Errors or Copy
If the JSON is invalid, inspect the line error marker. If valid, copy the formatted output or download as a .json file.
Key Settings & Parameters
| Setting | What It Controls | Recommended Default |
|---|---|---|
| Indentation Spacing | Sets spacing width: 2 spaces is standard for modern web development, 4 spaces is common in Python/enterprise tooling. | 2 spaces for web development |
| Minify | Strips all unnecessary whitespace and newlines, condensing the JSON into a minimal byte payload. | Use for production API payloads and storage |
Common Pitfalls to Avoid
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• Leaving trailing commas in arrays or objectsJSON does not permit trailing commas after the last element. Remove the comma before closing brackets.
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• Using single quotes ('key') instead of double quotes ("key")The JSON specification strictly requires standard double quotes for all keys and strings.
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• Pasting unquoted JavaScript object keys{ name: "test" } is valid JS, but invalid JSON. All keys must be wrapped in double quotes: { "name": "test" }.
Pro Tips for Best Results
- Use the Minify feature before sending data over webhooks to shave up to 30% off payload size.
- Check the character counter to verify your payload stays within database column constraints.
Local Processing Guarantee
Runs strictly client-side. Proprietary API keys, user payloads, and database dumps are never transmitted anywhere.
When to Use
- Formatting minified API responses during software development and debugging.
- Validating configuration files (package.json, tsconfig.json, docker-compose) for syntax errors.
- Minifying JSON payloads to reduce bandwidth before transmitting over webhooks or storing in databases.
Formatting JSON5, YAML, or JavaScript objects containing functions, comments, or undefined values (use specific converters for those).
- • JavaScript engines represent numbers using 64-bit floating point (IEEE 754). Integers exceeding Number.MAX_SAFE_INTEGER (9,007,199,254,740,991) may experience precision loss if unquoted.