{} JSON Validator & Formatter
Validate, format, and minify JSON. Error messages with line numbers.
How to Use This Tool
Paste any JSON string into the input box and the validator checks it in real time. You can then format it for readability or minify it for transmission. The tree view breaks down complex nested structures so you can inspect them at a glance.
Paste your JSON into the Input JSON textarea. The status badge updates instantly.
Click Format / Pretty Print to indent the output with 2-space nesting.
Click Minify to collapse the JSON to a single compact line for API payloads.
Use Copy Output to grab the result, or review the JSON Tree for a visual breakdown.
Why JSON Validation Catches Real Bugs
JSON has strict syntax rules that trip up developers daily. A trailing comma after the last key in an object is valid JavaScript but breaks JSON parsing entirely: {"name":"Alice",} throws a SyntaxError in every compliant parser. Single-quoted strings are another common source of errors when copying from JavaScript code: {'key': 'value'} is not valid JSON even though it looks fine. Unquoted keys like {key: "value"} fail for the same reason. Numbers with leading zeros are also rejected: {"code": 007} is invalid. Comments are not supported in JSON at all, so pasting configuration files that include // comments or /* block comments */ will cause parse failures. This validator gives you exact error messages so you can fix issues without guessing. For API debugging, paste the raw response body here to confirm whether the server is actually returning well-formed JSON before you write any parsing code.
Common Use Cases
Frequently Asked Questions
What does JSON validation check?
It checks for valid syntax: proper quotes around keys, correct brackets, valid value types, no trailing commas, and valid escape sequences.
Can I format minified JSON?
Yes! Paste minified JSON and click Format to get beautifully indented, readable output.
What is the difference between JSON and JavaScript objects?
JSON requires double-quoted keys and string values. JavaScript objects allow single quotes, unquoted keys, functions, and undefined.
What are common JSON errors?
Trailing commas (not allowed in JSON), single quotes instead of double, unquoted keys, undefined/NaN values.
Can I minify JSON?
Yes β click Minify to remove all whitespace for compact transmission.