JSON Formatter & Validator
Beautify, minify and validate JSON. Paste below and get instant feedback, syntax highlighting and clean error reporting.
Live formatting as you type. Select all with Ctrl/Cmd+A.
Everything runs locally in your browser — your JSON never leaves this page. Inputs and settings are remembered between visits.
About this tool
This free online tool runs entirely in your browser. Your data never leaves your device — there is no server processing, no tracking, and no signup required. Use it as often as you need, on any device.
· Maintained by the Forge Engineering Team
How This Calculator Works
This tool validates, formats, and minifies JSON (JavaScript Object Notation) data as specified in ECMA-404 and RFC 8259. Parsing uses the native JSON.parse() method, and formatted output is generated with JSON.stringify(obj, null, 2). Syntax errors are caught and reported with line/column information. All processing is done entirely in your browser — no data is transmitted.
Frequently Asked Questions
What is the difference between JSON and JSONP?
JSON is a data format. JSONP (JSON with Padding) wraps JSON in a function call to bypass same-origin restrictions in older browsers. JSONP is largely obsolete now that CORS (Cross-Origin Resource Sharing) is universally supported.
Can JSON contain comments?
No. Standard JSON (ECMA-404) does not support comments. This is a deliberate design choice. If you need comments, use JSONC (JSON with Comments, used in VS Code settings) or JSON5, but these are non-standard extensions.
What characters need escaping in JSON?
Double quotes (") and backslash (\) must be escaped. Control characters like newline (\n), tab (\t), and carriage return (\r) use backslash sequences. Unicode characters use \uXXXX. Forward slashes (/) do NOT need escaping despite common misconception.
Sources & References
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