< Codevup />

Online JSON Formatter and Validator

Input
Output
What is an online JSON formatter and validator?
An online JSON formatter (also called a JSON beautifier or JSON prettifier) takes raw, compressed, or minified JSON and reformats it with proper indentation and line breaks, making it easy to read and debug. At the same time, a JSON validator checks that the input is syntactically correct and immediately reports any errors — such as missing quotes, trailing commas, or mismatched brackets.
How do I prettify or beautify JSON online?
Paste your JSON into the left panel and click Prettify. The formatted output appears instantly in the right panel. You can choose between 2-space and 4-space indentation to match your project style. The result is ready to copy with a single click.
How do I minify or compress JSON?
Click the Minify button in the toolbar. This strips all whitespace and newlines from your JSON, producing the most compact valid representation. Minified JSON is ideal for reducing API payload sizes, optimizing network transfers, and storage.
How does JSON validation work?
As you type, the tool attempts to parse your JSON in real time. If the input is valid, a green Valid badge appears in the output panel. If not, a red error message at the bottom shows the exact parse error — including the position of the unexpected token — so you can fix it immediately.
What are the most common reasons JSON is invalid?
The most frequent JSON errors are: keys not wrapped in double quotes (single quotes are not valid JSON), trailing commas after the last item in an array or object, unescaped special characters inside strings, and mismatched or missing braces and brackets. The error message will point you to the exact location of the problem.
Is my JSON data safe and private?
Yes. All formatting and validation happens entirely inside your browser using JavaScript. Your JSON is never uploaded to or stored on any server. This makes the tool safe to use with sensitive or confidential data.
Should I use 2-space or 4-space indentation?
Both are widely accepted. 2-space indentation is the default in most JavaScript and Node.js projects, as well as tools like JSON.stringify with a space argument of 2. 4-space indentation is common in Python (via json.dumps) and some Java environments. Choose whichever matches your codebase or style guide.
Can I format large JSON files?
Yes. Because everything runs locally in your browser, there is no server-side file size limit. Very large JSON documents may cause a brief processing delay depending on your device, but the tool will handle them without any upload restrictions.
What is JSON?

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format originally derived from JavaScript object literal syntax. It was standardized in RFC 8259 and is now language-independent, with parsers available in virtually every programming language.

A JSON document is built from six value types: strings (double-quoted), numbers, booleans (true / false), null, arrays (ordered lists wrapped in []), and objects (key-value maps wrapped in {}). Every key in an object must be a double-quoted string, and trailing commas are not allowed.

JSON is the dominant format for REST APIs, browser storage (localStorage, IndexedDB), configuration files in JavaScript projects (package.json, tsconfig.json), and NoSQL databases like MongoDB and Firestore. Its simplicity and native support in browsers make it the default choice for machine-to-machine data exchange on the web.