Check if a string is valid JSON and learn the root type (object, array, string, number, boolean, null). Catch syntax issues before they break an API client. Validation is local.
Everything runs in your browser. Your input is not sent to a server by this tool.
Open the JSON Validator, enter your input, and run the action. Results appear on the same page so you can copy or download without leaving the tool.
The JSON Validator processes data with client-side JavaScript where the implementation allows, so core input stays in your browser session for that step.
Get a quick, free result for everyday tasks without installing software or creating an account on a separate service.
No—this checks JSON syntax, not a specific schema.
Yes.
Double-check important outputs before using them in documents or production systems. Keep original files when working with uploads until you confirm the result.
ToolBoxy keeps the Free JSON Validator free and simple: open the page, finish the task, and move on—no account wall. Related tools on this page point you to the next step.