Pure front-end local processing · Data never uploaded · Format/Minify/Validate/JSONPath query all-in-one
Zero dependencies · Works offlineJSON (JavaScript Object Notation) is the de facto standard format for modern web development, API interfaces, and data exchange. However, JSON returned from servers or extracted from logs is often minified into a single line, making it hard to read. Our Online JSON Formatter runs entirely in your browser, providing an all-in-one solution with formatting/beautifying, minifying, syntax validation, error positioning, collapsible tree view, and JSONPath query.
Unlike most online JSON tools, we never upload your data to any server. All parsing and formatting operations are performed on your device, so it works even without an internet connection. This is especially important when handling JSON containing sensitive information (such as API keys, user data, or internal configurations).
JSONPath is a query language for extracting data from JSON documents. Its syntax is similar to XPath but designed specifically for JSON.
JSON syntax is very strict. Common errors include trailing commas, unquoted keys, using single quotes instead of double quotes, and unclosed brackets. Our validator not only tells you "syntax error" but also precisely locates the line and column number of the error and highlights the error context, helping you fix problems in seconds.
Absolutely not. This tool is built with pure front-end technology. All JSON parsing, formatting, validation, and querying happen in your browser. You can press F12 to open Developer Tools and check the Network panel to confirm there are no data upload requests. The tool works normally even without an internet connection.
There is no hard limit in theory, but due to browser memory and performance constraints, we recommend processing JSON files no larger than 10MB. For very large JSON files (such as log files of hundreds of MB), we suggest pre-processing with a command-line tool (like jq) first, then using this tool to view the formatted result.
The JSON standard allows non-ASCII characters to appear directly (UTF-8 encoding), but some systems generate JSON that escapes non-ASCII characters into \uXXXX format. This is valid JSON. If you want readable characters, this tool preserves the original characters during formatting (it does not decode Unicode escapes), but you can use the "Unescape" feature to restore \uXXXX back to readable characters.
This tool supports a common subset of JSONPath syntax: root object access ($), property access ($.key), array index ($[0]), array wildcard ($[*]), recursive search ($..key), and simple filter expressions ($.arr[?(@.prop>1)]). Complex script expressions and custom functions are not currently supported.
Yes. The formatted JSON is standard, valid JSON. If you need to embed JSON into a JavaScript code string, we recommend using the "Escape" feature to automatically escape special characters like double quotes with \ prefixes, avoiding string parsing errors.
Formatted Text is a standard JSON string, suitable for copying and pasting or saving as a file. Tree View is an interactive structural display where objects and arrays can be clicked to collapse/expand, making it easier to browse the hierarchical relationships of large JSON. The content is identical in both; only the presentation differs.