About the JSON Formatter & Validator
Format and validate JSON locally, including Beautify, Minify, copy and download.
Formula or method
JSON.parse validates syntax; JSON.stringify rewrites the result with compact or indented whitespace.
Worked example
{"ok":true} becomes a readable object with indentation.
How to use the tool
- Paste JSON text or import a JSON file; verify the syntax message is valid.
- Choose Beautify for indentation or Minify for a compact representation.
- Copy or download the result and inspect it before pasting it into configuration files.
When this tool is useful
Validate JSON syntax, make nested structures readable, and download the formatted result.
What to check before relying on the result
Syntax validation is not JSON Schema validation. Duplicate object keys are not flagged; very large inputs have a browser processing limit.
Assumptions and limitations
Syntax validation does not check duplicate keys or JSON Schemas.
Frequently asked questions
What is JSON beautification?
Adding predictable indentation and line breaks to valid JSON.
Why does my JSON file show an error near a trailing comma?
JSON does not allow trailing commas or comments. Remove them and check that keys and string values use double quotes.
Continue with a related workflow
Privacy and support
Your inputs are processed locally in your browser. ToolMosaic does not upload or store the values you enter in this tool. Our tools are free, and we appreciate your support.