Paste or upload raw JSON on the left and get prettified, validated output on the right.
A JSON formatter is a tool that takes raw, unstructured JSON—often minified or poorly indented—and transforms it into human-readable form by adding consistent line breaks, indentation, and syntax highlighting. Whether you’re debugging a payload in your API response, inspecting a configuration file, or simply trying to make sense of nested data, a formatter helps you visually parse keys and values at a glance.
Beyond just prettifying, many formatters also validate your JSON on the fly, flagging stray commas, unmatched braces, or invalid tokens with clear error messages. This immediate feedback speeds up development by catching typos or structural mistakes before they propagate into runtime errors or broken integrations.
Advanced JSON formatter tools support features like adjustable indentation (tabs vs. spaces), theme switching (light vs. dark mode), clipboard copy, and large-file handling. Some even let you collapse and expand object trees for focused navigation, making it easy to drill into deeply nested structures without losing context.
Our formatter instantly validates your JSON and displays precise error messages with line and column numbers to help you locate and fix issues quickly.
Absolutely. All formatting and validation happens entirely in your browser. Your JSON data never leaves your device or gets sent to any server.
You can adjust indentation size (2 or 4 spaces), choose between spaces and tabs, and toggle syntax highlighting to customize the output to your preferences.
Yes, our formatter is optimized for performance and can handle JSON files up to several megabytes in size. For extremely large files, you might experience slightly longer processing times.
Common JSON syntax errors include missing quotes around property names, trailing commas, single quotes instead of double quotes, and unmatched brackets or braces. Our validator will help identify these issues.
Yes, you can copy the formatted JSON to your clipboard using the copy button or download it as a .json file with the download button.
No, this tool strictly validates against the standard JSON specification. Extended formats like JSONP, JSON5, or JSON with comments are not supported and will trigger validation errors.
Yes, you can use Ctrl+Enter (or Cmd+Enter on Mac) to format your JSON, Ctrl+S to save, and Ctrl+Shift+C to copy the formatted result.
