JSON Validator
Check whether your JSON is valid, and find out exactly why it is not.
Runs entirely in your browser — your data is never uploaded to any server.
How it works
- Paste your JSONAny size, any structure.
- Run validationSyntax is checked instantly.
- Fix or continueErrors show the exact position.
What this tool does
- Exact line, column and character position for errors
- Shows the surrounding snippet so the problem is obvious
- Structure summary for valid documents
- Runs offline in your browser
Frequently Asked Questions
Double-quoted keys and strings, no trailing commas, no comments, and no JavaScript-only values such as undefined or NaN.
Not here — this checks syntax. JSON Schema validation is a separate concern requiring your schema document.
No. The specification has no comment syntax. Formats like JSON5 or JSONC add them, but standard parsers reject them.
Yes. Validation is entirely local.
Privacy and security
Your input is processed by JavaScript running inside your browser. Nothing you paste is sent over the network, logged, or stored — which is what makes this safe to use with production data. If you want to check this yourself: open your browser’s developer tools, switch to the Network tab, and use the tool — you will see no request carrying your file or input leave the page.
Related tools
View all tools →JSON FormatterTurn unreadable JSON into properly indented, readable structure.JSON MinifierStrip every unnecessary byte from your JSON.JSON BeautifierExpand minified JSON into something a human can actually read.YAML FormatterFormat, validate and convert YAML.XML FormatterIndent and check XML documents.