JSON Validator
Check whether JSON is well-formed. Errors are reported locally — nothing leaves your browser.
Drop a file or paste below
Validate JSON locally
How to use this tool
Add JSON
Paste text or drop a .json file.
Validate
The browser parser reports success or the exact error.
Fix and retry
Edit in place until validation passes.
Catch bad JSON before deploy
A missing comma or trailing character can break an API client. Validate in the browser to confirm the document parses before you commit or publish.
Private by design
Configs often contain secrets. Validation uses the built-in JSON parser on your device — Format Convertly never sees the payload.
What “valid” means here
This tool checks syntax (parseability), not a JSON Schema. Use a schema validator separately if you need field-level contracts.
Frequently Asked Questions
More on quality loss: conversion quality guides · compression guides
Is my file uploaded?
No. Format Convertly tools run in your browser tab. Files are not sent to our servers for processing.
Is this tool free?
Yes. Use it without an account or watermark.
Does it work on mobile?
Yes — any modern phone or desktop browser that supports the required Web APIs.
Does it validate against a schema?
No — it checks that the text is valid JSON. Schema validation is a separate concern.
Ready to convert more formats?
Browse converters or jump back to the tool above.