What is JSON formatter?
JSON formatter makes API responses and config files readable. It validates the JSON, tells you exactly where an error is, pretty-prints it with your preferred indentation, or minifies it for production. Parsing runs in a Web Worker so even multi-megabyte JSON does not freeze the page.
When to use it
- Read a minified API response while debugging.
- Find the missing comma in a config file.
- Minify JSON before embedding it in code.
- Explore deeply nested data with the tree view.
Tips for the best result
- Errors show line and column – click Go to error to jump there.
- Tree view nodes collapse and expand with Enter or Space.
- Your JSON never leaves the browser, so it is safe for tokens and private data.
Limits and privacy
Comments and trailing commas are not valid JSON and will be reported as errors. Processing happens entirely in your browser, so your data never leaves your device and there is nothing to sign up for. Files are processed in your browser and never uploaded.
Related tasks
Many people who use JSON formatter also need Text diff checker or Image to Base64, and Case converter is one click away. Every MondayKit tool works the same way – open the page, add your input, get the result – with no account, no watermark and no upload.