JSON Formatter
& Validator

JSON has strict syntax rules. Common errors: trailing commas after the last item in an array or object (valid in JS but not JSON), single quotes instead of double quotes around strings, unquoted property names, undefined or NaN values (not valid in JSON), and comments (JSON has no comment syntax). Paste your JSON here and the validator will highlight the exact line causing the error.

JSON (JavaScript Object Notation) looks similar to a JS object but is stricter: all property names must be double-quoted strings, values can only be strings, numbers, booleans, null, arrays, or objects — no functions, dates, undefined, or NaN. JSON is a text format for data exchange, not executable code. Use JSON.parse() to convert JSON text to a JS object and JSON.stringify() to go the other way.

Minifying removes all whitespace (spaces, tabs, newlines) that isn't inside a string value. It makes the JSON smaller for network transmission — a large formatted JSON file can be 30–50% larger than its minified equivalent. Use formatted JSON for debugging and configuration files; use minified JSON for API responses and production data transfers to save bandwidth and reduce load times.

JSON Schema is a vocabulary for validating the structure of JSON data. It lets you define required fields, data types, value ranges, and patterns. For example, you can specify that an 'age' field must be a number between 0 and 120. It's widely used in APIs, configuration validation, and form builders. Tools like ajv (JavaScript) and jsonschema (Python) can validate data against a schema at runtime.

Standard JSON cannot contain comments — this is by design to keep it a simple data-interchange format. However, some tools accept JSON5 (a superset of JSON that allows // and /* */ comments) or JSONC (JSON with Comments, used by VS Code for config files). If you need comments in config files, consider YAML or TOML which both natively support them. Never include comments in API payloads.