JSON Formatter

JSON (JavaScript Object Notation) is the lingua franca of modern APIs and data exchange. It's lightweight, human-readable, and natively supported in virtually every programming language. But working with raw JSON — especially minified API responses, single-line log payloads, or deeply nested configurations — is painful without a formatter.

This tool does three things at once: it validates your JSON (instantly shows you if there's a syntax error and where it is), formats it with consistent 2-space indentation, and highlights the structure so objects, arrays, strings, and numbers are visually distinct. It also handles the most common JSON pitfalls: trailing commas (valid in JavaScript objects but not in JSON), single quotes (JSON requires double quotes), and unquoted keys.

Beyond basic formatting, a well-structured view reveals structural problems that are hard to spot in minified JSON: missing closing brackets, mismatched nesting, accidentally stringified numbers (like `"count": "42"` instead of `"count": 42`), and null vs undefined issues.

The minify mode reverses the process — it strips all whitespace and produces the most compact representation, which reduces payload size when sending data over a network. A typical API response formatted for readability might be 15-20KB; the same data minified might be 5-6KB.

Both formatting and minification run locally in your browser. Paste a 10MB JSON file and it processes in under a second without uploading anything.