JSON ToolsLocal
JSON Formatter + Validator
Validate, format, minify, and repair common JSON mistakes.
JSON Tools
JSON Validator
Paste JSON to check if it is valid and jump straight to the error.
InputJSON
OutputFormatted, validated, or minified JSON
Works onAny modern browser
About this tool
Validates JSON against the spec, reports the first parse error, and formats the valid result so you can confirm and reuse it.
Common use cases
- Clean up JSON before pasting it into code, config, or APIs.
- Validate JSON payloads and spot the error location quickly.
How to use it
- Paste JSON or upload a .json file.
- Run Format and validate to check the syntax.
- If it is invalid, read the error detail and review the suggested repaired output.
- Copy or download the validated JSON.
Best for
- Debugging API payloads before sending them to another system
- Cleaning pasted JSON into a readable structure for reuse
- Checking syntax and then copying a corrected JSON block back into code or config
Input and output notes
- Accepted inputs: .json.
- Exports are generated locally in the current browser session.
Limits to know
- Large pasted documents can be slower on lower-memory devices.
- Invalid source data must still be corrected before export.
Privacy
This tool runs in the browser, so pasted content and uploaded files stay on the current device during normal use.
Common next steps
JSON Formatter + Validator
Stay inside the JSON workflow when you need validation, formatting, or export in the next step.
JSON MinifierStay inside the JSON workflow when you need validation, formatting, or export in the next step.
YAML to JSONStay inside the JSON workflow when you need validation, formatting, or export in the next step.
Choose the right JSON page
Use JSON Formatter + Validator for the main edit flow
Choose the formatter when you want readable output, error reporting, and a cleaned copy in one page.
Use JSON Validator for syntax checks onlyChoose the validator when the search intent is about checking whether JSON is valid before you paste it elsewhere.
Use JSON Minifier for compact payloadsChoose the minifier when the output needs to be as small as possible for transport, embedding, or storage.
Common questions
How do I know if my JSON is valid?
Paste it and run validate. A green status confirms valid JSON; an error message shows what broke and where so you can fix it.
Is my JSON uploaded anywhere?
No. Validation runs entirely in your browser, so the JSON never leaves your device.
What are the most common JSON errors?
Trailing commas, missing quotes around keys, single quotes instead of double quotes, and unclosed brackets. The validator points you to the first failure.