Tool
JSON Formatter
Paste raw JSON to format, validate and syntax-highlight it. Switch to Minify to compress it. All processing runs in your browser.
About the JSON Formatter
JSON (JavaScript Object Notation) is a lightweight data format used by virtually every web API, configuration file, and database. Raw JSON from an API response or log file is often minified — all on one line with no indentation — which makes it nearly impossible to read. This tool reformats it into a structured, indented layout with colour-coded syntax highlighting.
The Format mode takes any valid JSON and outputs it with consistent indentation (2 or 4 spaces). Keys are highlighted in blue, string values in green, numbers in purple, booleans in amber and null in red. The Minify mode removes all whitespace and newlines, producing the smallest possible JSON for transmission.
The Validate button checks if your JSON is syntactically correct without formatting it. If the JSON is invalid, the error message shows exactly what is wrong and where.
Common mistakes that fail JSON validation: trailing commas after the last item in an array or object (valid in JavaScript but not JSON), single quotes instead of double quotes around strings, unquoted property keys, and comments (JSON has no comment syntax). This validator catches all of them.
JSON is used in API responses, configuration files (package.json, tsconfig.json, .eslintrc), database records in document stores like MongoDB, and data interchange between services. Being able to quickly format and validate a JSON blob is one of the most-used developer tasks — and this tool does it with no install required.
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