What is JSON?
JSON (JavaScript Object Notation) is a lightweight data-interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It is widely used in web APIs, configuration files, and data storage.
Why Format JSON?
Raw JSON from APIs or databases is often minified — compressed into a single line with no spaces or indentation. This makes it nearly impossible to read. Formatting (also called "beautifying" or "pretty-printing") JSON adds proper indentation and line breaks so you can easily understand the structure.
Common JSON Errors
- Missing commas — Every property and array element must be separated by a comma, except the last one.
- Trailing commas — Unlike JavaScript, JSON does not allow trailing commas after the last item.
- Single quotes — JSON requires double quotes for all strings. Single quotes are not valid.
- Unquoted keys — All keys must be enclosed in double quotes.
- Comments — JSON does not support comments. Remove them before parsing.
How to Use Our JSON Formatter
- Paste your JSON text into the input field.
- Click "Format / Beautify" to add proper indentation.
- Click "Minify" to compress the JSON to a single line.
- If your JSON has errors, you will see a helpful error message pointing to the issue.
JSON vs YAML vs XML
JSON is the most popular data format for web APIs because it is compact, human-readable, and natively supported by JavaScript. YAML is more readable but less compact. XML is more verbose and less popular for modern APIs.
Best Practices for JSON
- Use descriptive key names (e.g.,
"firstName"instead of"fn") - Keep nesting shallow — deep nesting is hard to read
- Use arrays for ordered lists of similar items
- Validate your JSON before sending it to an API
Our free JSON Formatter tool runs entirely in your browser — your data is never sent to any server, making it completely private and secure.