Is my JSON sent to a server?

No. Formatting, validation, and minification all run in your browser. Nothing is uploaded or logged.

Does the tool support large JSON files?

Yes. Files up to several megabytes format instantly. Very large payloads (50 MB+) may slow the browser since everything stays in memory.

The most common causes are trailing commas, single quotes instead of double quotes, and comments. JSON does not allow any of these.

No. Standard JSON does not permit comments. Strip the comments first, or use a dedicated JSONC parser.

Formatters

Format, validate, and minify JSON with syntax highlighting and error reporting.

Input

Output

Output will appear here

How to format and validate JSON

Paste JSON into MakeMyDev, click Format, and copy or download the result. Everything runs locally in your browser.

Paste JSON input
Paste or type your JSON into the input box. Invalid JSON will be highlighted with a line and column number.
Pick an action
Click Format to pretty-print, Validate to check without changing the text, or Minify to strip whitespace.
Review the output
The syntax-highlighted result appears on the right. Errors include the position so you can fix them quickly.
Copy or download
Use the Copy button for the clipboard or Download to save a .json file.

? Is my JSON sent to a server?: No. Formatting, validation, and minification all run in your browser. Nothing is uploaded or logged.
? Does the tool support large JSON files?: Yes. Files up to several megabytes format instantly. Very large payloads (50 MB+) may slow the browser since everything stays in memory.
? Why does my JSON fail to validate?: The most common causes are trailing commas, single quotes instead of double quotes, and comments. JSON does not allow any of these.
? Can I format JSON with comments (JSONC)?: No. Standard JSON does not permit comments. Strip the comments first, or use a dedicated JSONC parser.