JSON Formatter & Validator
A malformed API response, a config file with a missing comma, or a wall of unindented JSON copied from a log file — spotting the exact problem by eye is tedious. This tool checks whether your JSON is valid and, if it is, formats it with proper indentation so the structure becomes easy to read.
What "Format & Validate" actually checks
The tool attempts to parse your input as JSON using the same strict parsing rules any programming language's JSON parser follows. If parsing fails — due to a missing comma, an unquoted key, a trailing comma, or mismatched brackets — it shows the specific error message describing what went wrong and roughly where, rather than just saying "invalid." If parsing succeeds, it re-outputs the JSON with two-space indentation so nested objects and arrays are visually clear.
Where this fits into a workflow
Debugging why an API integration is failing by checking whether the response body is actually valid JSON before assuming the problem is elsewhere in the code. Reviewing a configuration file (like a package.json or a settings file) that's been hand-edited and needs a structure check before deploying. Making a minified, single-line JSON blob (common in API responses or log output) human-readable for debugging, then minifying it back down afterward for use in code.
Frequently Asked Questions
Why does my JSON fail validation even though it looks correct? Common invisible issues include trailing commas after the last item in an object or array (which JavaScript objects allow but strict JSON does not), single quotes instead of double quotes around keys and strings, or an unquoted key name — all valid in JavaScript object literals but not in strict JSON.
What does the Minify button do? It re-outputs the same valid JSON with all unnecessary whitespace and line breaks removed, useful when you need a compact single-line version for embedding in code or a URL parameter.
Is my JSON data uploaded anywhere? No — parsing and formatting happen entirely in your browser using JavaScript's built-in JSON functions; nothing is sent to a server.