JSON Validator
Paste JSON below. Validity, formatting, and structure stats update as you type.
New to data formats? Read: JSON vs. XML vs. CSV
Getting a confusing parse error? Read: Common JSON Syntax Errors
How it works
This validator parses your input using JavaScript's native JSON parser, pinpoints exactly where parsing failed if it's invalid, and pretty-prints the result the moment it's confirmed valid — entirely in your browser, with nothing uploaded to a server.
When you’d use this
- Checking whether an API response or config file is well-formed before it breaks something downstream
- Debugging a hand-edited JSON payload that's throwing a parse error elsewhere
- Validating data that contains real user information or API keys without sending it over the network
Common questions
Is this JSON validator really free?+
Yes, completely free with no limits, no signup, and no watermarks. All 20+ tools on Datavo are free to use.
Does my JSON data get uploaded anywhere?+
No. Validation happens entirely in your browser using JavaScript's built-in JSON parser. Nothing you paste is ever sent to a server — you can even disconnect from the internet after the page loads and it will still work.
Why does it say my JSON is invalid when it looks fine?+
The most common causes are trailing commas (not allowed in strict JSON), single quotes instead of double quotes, or an unescaped quote inside a string. The error message includes the position where parsing failed, which usually points right at the issue.
Can I validate very large JSON files?+
Yes — since everything runs locally in your browser, there's no server-imposed file size limit. Very large files (tens of megabytes) may be slower to format since your device is doing all the work, but there's no hard cap.
What's the difference between validating and formatting?+
Validating checks whether the JSON syntax is correct. Formatting (also called "pretty-printing") re-indents valid JSON to be more readable. This tool does both at once — you'll see the formatted, indented version the moment your JSON is confirmed valid.