Key takeaways
- 01Formatting makes JSON easier to read, while minifying removes extra whitespace for compact storage or transfer.
- 02Validation catches syntax issues like trailing commas, single quotes, unquoted keys, and comments.
- 03The formatter uses the browser's JSON parser, so pasted data is not uploaded to Handytool.
Why format JSON?
JSON is easy for software to read, but raw API responses and config blobs can be painful for people. Pretty-printing adds indentation and line breaks so nested arrays, objects, strings, numbers, booleans, and null values are easier to inspect.
The same tool can also minify JSON when you need a compact one-line payload, or validate it when a parser, API, build step, or config file complains.
How to format JSON online
Paste only data you are allowed to inspect locally, especially when working with production payloads.
- 01
Open the JSON formatter
Paste JSON into the input pane or attach a JSON file from your device.
- 02
Choose indentation
Select 2 spaces, 4 spaces, or tabs to match your project or editor style.
- 03
Format, minify, or validate
Click Format for readable output, Minify for compact output, or Validate to check the JSON syntax.
- 04
Copy or download
Copy the output or download it as a JSON file after confirming the result parses correctly.
Common invalid JSON mistakes
JSON is stricter than many JavaScript object examples you see in code snippets.
- 01Trailing commas after the last object property or array item.
- 02Single quotes instead of double quotes around strings.
- 03Object keys that are not wrapped in double quotes.
- 04Comments inside the JSON.
- 05Missing commas between properties or array items.
What happens to the JSON?
The formatter parses and serializes JSON in your browser with JavaScript's built-in JSON support. Handytool does not need to upload your payload, config file, or data dump.
Very large JSON documents can still use significant memory in the browser. For huge exports, consider formatting only the section you need to inspect.
JSON formatter FAQ
Can I format JSON without uploading it?
Yes. Handytool formats, minifies, and validates JSON in the browser.
What is the difference between format and minify?
Format adds line breaks and indentation for readability. Minify removes optional whitespace to make the JSON smaller.
Why does valid JavaScript fail as JSON?
JSON has stricter syntax than JavaScript object literals. It does not allow comments, single-quoted strings, functions, undefined, or unquoted keys.
Can I attach a JSON file?
Yes. Attach a JSON or text file, then format, minify, validate, copy, or download the result.