JSON Formatter & Validator
Paste JSON to pretty-print, minify, or check it for errors. Everything runs in your browser — nothing is uploaded.
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Format, minify, and validate JSON
Turn compact JSON into an indented structure, reduce formatted JSON to a smaller single line, or identify syntax errors before sending a request or saving a configuration file.
Step by step
- Paste a JSON object, array, string, number, boolean, or null.
- Use Format for readable indentation or Minify for compact output.
- If validation fails, use the error details to fix the input and try again.
Common uses
- Inspect API responses and webhook payloads.
- Clean up configuration files for code review.
- Reduce whitespace before copying JSON into a request.
Good to know
JSON requires double quotes around property names and strings. It does not allow comments or trailing commas. Formatting can normalize whitespace but does not confirm that values match an API’s business rules.
Frequently asked questions
Why is my JavaScript object not valid JSON?
JavaScript object literals may use single quotes, unquoted keys, comments, undefined, or trailing commas; standard JSON does not.
Is pasted JSON sent anywhere?
No. Parsing, formatting, and validation happen in your browser.
Tool and instructions reviewed October 2026.