JSON Formatter & Validator - Beautify & Validate
Format and validate your JSON data instantly. Our free tool checks syntax, beautifies with proper indentation, and can minify JSON for production use.
Understanding This Tool
What It Does
Format and validate JSON code to ensure it's syntactically correct. This tool automatically indents JSON, highlights errors, and shows you exactly what's wrong with invalid JSON syntax.
Understanding the Results
- Syntax Status: Valid or invalid JSON indication
- Error Location: Line and column number of any syntax errors
- Error Description: Explanation of what's wrong
- Formatted Output: Pretty-printed version of the JSON
- Structure View: Collapsed/expandable view of JSON hierarchy
Common Use Cases
- Code Development: Check JSON syntax while coding
- API Testing: Validate JSON responses from APIs
- Configuration Files: Verify JSON config file syntax
- Data Transfer: Ensure JSON data is properly formatted
- Debugging: Find and fix JSON syntax errors quickly
Pro Tips & Best Practices
- Common Errors: Missing commas, trailing commas, and quote mismatches
- Pretty Print: Format for readability even if syntax is valid
- Minification: Remove formatting to reduce file size for transmission
Frequently Asked Questions
Valid JSON requires: double quotes (not single), no trailing commas, proper nesting, escaped special characters, and specific data types (string, number, boolean, null, array, object).
JSON is stricter: only double quotes, no comments, no trailing commas, no functions, no undefined. JavaScript objects are more flexible but not all JS objects are valid JSON.
No, standard JSON does not support comments. Some parsers allow comments as an extension, but portable JSON should never include them. Use separate documentation instead.
Common causes: trailing commas, single quotes instead of double, missing/extra brackets, unescaped special characters in strings. Use a validator to pinpoint the exact error location.
JSON5 is an extension allowing single quotes, trailing commas, comments, and unquoted keys - making it more JavaScript-like. It's not standard JSON and not universally supported.
Frequently Asked Questions
What makes JSON valid or invalid?
Valid JSON requires: double quotes (not single), no trailing commas, proper nesting, escaped special characters, and specific data types (string, number, boolean, null, array, object).
What's the difference between JSON and JavaScript objects?
JSON is stricter: only double quotes, no comments, no trailing commas, no functions, no undefined. JavaScript objects are more flexible but not all JS objects are valid JSON.
Can JSON have comments?
No, standard JSON does not support comments. Some parsers allow comments as an extension, but portable JSON should never include them. Use separate documentation instead.
How do I fix 'unexpected token' errors?
Common causes: trailing commas, single quotes instead of double, missing/extra brackets, unescaped special characters in strings. Use a validator to pinpoint the exact error location.
What's the difference between JSON and JSON5?
JSON5 is an extension allowing single quotes, trailing commas, comments, and unquoted keys - making it more JavaScript-like. It's not standard JSON and not universally supported.
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How this tool works: This tool runs in your browser and on our server in real time. Depending on the tool, results are computed directly from the input you provide or retrieved from live, authoritative data sources at the moment you run a lookup. We do not sell your data, and your lookups are kept private — any history shown here is stored only on your device.