Format JSON online: indentation and validation
Format and beautify your JSON in one click: automatic indentation, syntax highlighting and real-time validation.
Published on January 9, 2026Poorly formatted JSON is unreadable and difficult to debug. Whether you're working with REST APIs, configuration files or NoSQL databases, an online JSON formatter instantly transforms compact or broken JSON into a readable, indented structure.
Understanding the conversion
JSON formatting consists of adding spaces, line breaks and consistent indentation to make the tree structure visible. A good online formatter also performs validation: it checks that the JSON complies with the RFC 8259 standard (commas, double quotes, no comments). In case of an error, it indicates the faulty line and character.
📊 Conversion table
| Compact JSON (minified) | Formatted JSON (2-space indent) |
|---|---|
| {"name":"Alice","age":30} | { "name": "Alice", "age": 30 } |
| [1,2,3] | [ 1, 2, 3 ] |
| {"a":{"b":"c"}} | { "a": { "b": "c" } } |
💡 Practical examples
Copy the raw JSON response from your API (often on a single line), paste it into the formatter and get a readable structure with 2-space indentation.
Paste your package.json into the formatter. If a comma is missing or a quote is mismatched, the tool signals the error with the exact position.
A JSON formatter also offers the reverse option: minification. It removes all spaces and line breaks to reduce the weight of files sent over the network.