JSON Formatter & Validator
Pretty-print & validate JSON
Formatted JSON will appear here
What Is the JSON Formatter & Validator?
The JSON Formatter & Validator pretty-prints, minifies, and validates JSON with clear, line-specific error messages and adjustable indentation. Paste raw or messy JSON to instantly format it for readability or compress it for production. Everything runs client-side, so even sensitive API payloads stay private on your machine.
Key Features
Why Format and Validate JSON
JSON from APIs and logs often arrives minified or malformed, making it hard to read or debug. Formatting adds consistent indentation so structure is obvious, while validation catches the trailing commas, missing brackets, and unquoted keys that break parsers. Together they turn an unreadable blob into something you can actually work with.
Pretty-Print vs Minify
Pretty-printing expands JSON with line breaks and indentation for human readability — ideal during development and debugging. Minifying strips all unnecessary whitespace to shrink payload size for transmission and storage. This tool does both, so you can read JSON while building and compress it before shipping.
Common Use Cases
- Making a minified API response readable
- Validating JSON before using it in code
- Minifying JSON to reduce payload size
- Debugging syntax errors in a config file
Frequently Asked Questions
How does the validator help me?
The validator checks your JSON against the spec and reports the exact problem and location, such as a missing comma or bracket, so you can fix syntax errors quickly instead of hunting through the document.
Can it handle large JSON files?
Yes, it processes large JSON documents efficiently in your browser. The practical limit is your device memory, which comfortably handles typical API responses and config files.
What is the difference between formatting and minifying?
Formatting (pretty-printing) adds indentation and line breaks for readability, while minifying removes all unnecessary whitespace to make the JSON as small as possible for transmission.
Is my JSON sent to a server?
No. All formatting and validation happens locally in your browser, so even sensitive API payloads never leave your machine.
Why does valid-looking JSON fail validation?
Common causes are trailing commas, single quotes instead of double quotes, unquoted keys, or comments — all of which are invalid in strict JSON even though they look fine. The error message will point to the issue.
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