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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 based on a subset of JavaScript but is language-independent and supported by virtually all modern programming languages.

What's the Difference Between JSON and XML?

JSON is more compact and easier to read than XML. JSON uses key-value pairs and arrays, while XML uses tags. JSON is typically faster to parse and has become the preferred format for web APIs. XML, however, supports attributes and namespaces, making it more suitable for complex document structures.

What Are Common JSON Syntax Errors?

Common JSON errors include: trailing commas after the last element, using single quotes instead of double quotes, unquoted property names, comments (JSON doesn't support comments), and using undefined or NaN values. Always validate your JSON to catch these errors early.

What Data Types Does JSON Support?

JSON supports six data types: String (text in double quotes), Number (integer or floating-point), Boolean (true or false), Null (empty value), Object (key-value pairs in curly braces), and Array (ordered list in square brackets). Note that JSON does not support undefined, functions, or dates natively.

How to Parse JSON in Different Programming Languages?

Here are examples of parsing JSON in various languages:

JavaScript: JSON.parse(jsonString) / JSON.stringify(object)
Python: import json; json.loads(string) / json.dumps(object)
Java: new ObjectMapper().readValue(json, Class.class) // Jackson
PHP: json_decode($json) / json_encode($array)
Go: json.Unmarshal([]byte(str), &obj) / json.Marshal(obj)
C#: JsonSerializer.Deserialize<T>(json) / JsonSerializer.Serialize(obj)

When Should I Format vs Minify JSON?

Format (prettify) JSON when you need to read, debug, or edit the data manually. Minify JSON when transmitting data over networks or storing in databases to reduce file size and improve performance. Minified JSON removes all unnecessary whitespace and newlines.

Why is JSON the Standard for Web APIs?

JSON became the standard for web APIs because it's lightweight, human-readable, and natively supported by JavaScript (the language of web browsers). It's simpler than XML, faster to parse, and works seamlessly with modern frontend frameworks like React, Vue, and Angular.

How to Validate JSON Data?

You can validate JSON using online tools like this formatter, or programmatically using try-catch blocks when parsing. For schema validation, use JSON Schema to define the structure your JSON should follow. Many IDEs also have built-in JSON validation features.