JSON Formatter

What Is JSON?

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that is easy for humans to read and write, and simple for machines to parse and generate. Originally derived from JavaScript, JSON has become the de facto standard for data exchange across virtually every programming language, REST API, and configuration file format in modern software development.

Why Format and Validate JSON?

When working with API responses, configuration files, or data exports, JSON is often delivered as a single compressed line. Formatting it with proper indentation and line breaks makes nested structures visible at a glance, letting you spot missing fields, mismatched brackets, or unexpected values in seconds. Validating JSON before sending it to an API or importing it into a database prevents hard-to-debug runtime errors caused by trailing commas, unquoted keys, or mismatched data types.

Common JSON Errors

The most frequent mistakes in hand-written JSON include trailing commas after the last item in an object or array, single quotes instead of double quotes around strings, unquoted property names, and missing closing brackets or braces. This tool pinpoints the exact line and position of the first syntax error so you can fix it quickly without guessing.

Format, Minify, or Validate

Use Format mode to pretty-print JSON with syntax highlighting for keys, strings, numbers, booleans, and null values. Minify mode strips all unnecessary whitespace to produce the smallest possible output, which is ideal for reducing payload size in API requests or storage. Validate mode checks whether your input is valid JSON and reports exactly where the first error occurs. All processing happens entirely in your browser — your data never leaves your device.