JSON / XML Formatter and Validator

Formatter and validator JSON · XML · Client side only

Waiting for input

Choose JSON or XML, paste your data into the left panel, then use the buttons to format and validate. On success you get a pretty printed version on the right. On error you get a human readable message with the parser’s feedback.

Input Paste raw JSON or XML here

Tip: keep sensitive data local, this tool does not send your content anywhere.

Formatted output Created only after a successful parse

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JSON mode. Uses JSON.parse and JSON.stringify for strict syntax checking.

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Paste JSON or XML on the left and choose the appropriate mode. Valid data will be reformatted on the right; any syntax errors will be reported here using the browser’s parser feedback.

How this tool behaves

Everything stays in your browser

All parsing and formatting happens locally using the JavaScript engine already built into your browser. JSON is handled with the native JSON methods. XML is handled with DOMParser and XMLSerializer.

That means you can safely test request payloads, API responses, and log snippets without sending them to a remote service. It is especially helpful when you are working with sample data that represents production systems.

In JSON mode, the tool requires proper quotes around keys, commas in the right places, and valid data types. The error messages come directly from JSON.parse.
In XML mode, the tool uses the browser’s XML parser to build a document tree, checks for parser error nodes, then pretty prints the result using standard start and end tags.
If something looks wrong, you get a human readable hint that points you toward the broken line or structure instead of a silent failure.

Client side only

No network calls

Useful for logs and APIs

! Legal and usage notice

This JSON / XML Formatter and Validator runs entirely in your browser. The page does not send your input to any remote server, does not store content, and does not attempt to infer or classify the data you paste. It simply uses built in browser parsing features to validate and reformat structured text.

Important. This tool is provided for convenience and basic syntax checking and does not replace full application testing, schema validation, or security review. It cannot guarantee that your data model, business logic, or integrations are correct or safe. You are solely responsible for how you use the tool and for keeping sensitive information under your control. No warranty of any kind is provided.