What is JSON?
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write, and easy for machines to parse and generate. JSON is built on two structures: a collection of name/value pairs (objects) and an ordered list of values (arrays). It is the standard format for API responses and configuration files.
How to Use a JSON Formatter Online
Paste your payload into the input panel and inspect the formatted structure in output for quick debugging. Use minify when you need compact JSON for transport or storage.
Why Format JSON?
Raw JSON data often comes as a single line of text to save space (minified). While this is efficient for computers, it is nearly impossible for humans to read or debug. A JSON Formatter takes this raw string and applies indentation and newlines, making the structure clear and readable.
Features of this Tool
- Pretty Print: Expands minified JSON into a readable tree structure with proper indentation.
- Minify: Removes all unnecessary whitespace and newlines to reduce file size for production use.
- Validation: Automatically checks for syntax errors (like missing commas or quotes) and tells you exactly what went wrong.
- Client-Side Security: Unlike many online tools, this formatter processes your data directly in your browser. Your sensitive JSON data is never sent to our servers.
Common JSON Errors
- Trailing Commas: JSON does not allow a comma after the last item in an object or array.
- Single Quotes: JSON keys and string values must be wrapped in double quotes ("), not single quotes (').
- Undefined Values: JSON strictly supports strings, numbers, objects, arrays, booleans, and null. It does not support 'undefined' or functions.
FAQ
Does this JSON validator send data to a server?
No. Formatting and validation are performed client-side in your browser session.
When should I use Format vs Minify?
Use Format while debugging and reviewing structure; use Minify before shipping payloads to reduce size.
Can this tool detect invalid JSON syntax?
Yes. It reports parse errors such as missing quotes, trailing commas, and malformed object or array structures.