JSON Formatting Basics for Beginners
Learn how JSON structure, indentation, commas, quotes, and validation work with a practical browser-based workflow.
JSON, short for JavaScript Object Notation, is a text format commonly used to exchange structured data between applications. It represents information using objects, arrays, strings, numbers, booleans, and null values. Proper formatting makes JSON easier for people to read and inspect, especially when a file contains nested data.
What valid JSON looks like
A JSON object uses curly braces and key-value pairs. Keys and string values use double quotes, and pairs are separated by commas. Arrays use square brackets. JSON does not allow comments or trailing commas, and strings must use valid escaping for special characters.
Common formatting mistakes
- Using single quotes around keys or string values.
- Leaving a comma after the final item in an object or array.
- Forgetting a closing brace or bracket.
- Using an unescaped quotation mark inside a string.
- Writing a value such as undefined, which is not a JSON value.
Format and validate JSON
- Open the JSON Formatter and Validator.
- Paste your JSON into the input area.
- Run the formatting or validation action provided by the tool.
- If an error appears, inspect the indicated area and correct the syntax.
- Copy the formatted output and test it in the application where it will be used.
Formatting versus validation
Formatting changes whitespace and indentation to improve readability. Validation checks whether the input follows JSON syntax. Valid JSON can still contain incorrect data for a particular application, so syntax validation is only one part of testing. Confirm that required fields exist and values have the expected types.
Handle data carefully
Before pasting data into any online tool, consider whether it contains credentials, personal information, or confidential business records. Use test or redacted data when possible, and verify the behavior of the tool you choose.
Next steps
After formatting, review the data structure and test the result in your development environment. You may also find the HTML Entity Encoder and Decoder useful when working with special characters, or the UUID Generator when you need a unique identifier.