What Is JSON?
A practical intro to JSON structure, syntax rules, and why formatting and validation tools are so widely used.
Original source title: JSON 是什么
Section 1
JSON stands for JavaScript Object Notation. Even though the name comes from JavaScript, JSON is now used almost everywhere: backend services, frontend apps, logs, configuration files, test tools, and automation systems. What made it popular is not that it is fancy, but that it is simple, structured, machine-friendly, and still readable to humans. For non-technical users, JSON can be understood as a text format for structured data, usually written as field names paired with values, such as a user profile, an order record, or a configuration object.
Section 2
In real software workflows, JSON appears almost everywhere. When you click a button on a website and a request goes to the server, the response is often JSON. When you inspect API output, config files, or system logs, the braces and brackets you see are often JSON as well. Its common building blocks are objects and arrays. Objects hold key-value pairs, and arrays hold multiple values or multiple objects. This structure makes JSON a strong fit for representing nested data, such as one user with multiple addresses or one order with multiple products.
Section 3
That is also why JSON tools are so common on online utility sites. Real-world JSON is often hard to read. A compressed one-line JSON response becomes painful when it gets large, and tiny syntax mistakes like a missing comma, broken quotes, or mismatched braces can cause the whole payload to fail. Formatting tools make the structure easier to read through indentation, while validation tools point out the exact place where the syntax breaks. For developers this saves debugging time, but product managers, testers, operators, and even office users also benefit when they need to inspect structured data quickly.
Section 4
A common beginner mistake is to treat JSON like ordinary text. JSON has strict syntax rules. Keys usually need double quotes, string values need double quotes as well, comments are not allowed in standard JSON, and trailing commas can break parsing. Because the rules are strict, machines can process it reliably, but people can also make small mistakes easily. A good tutorial therefore should not stop at saying “JSON is a data format.” It should connect JSON to real tasks such as checking API responses, editing configuration, reading logs, or cleaning exported structured data. That context makes it clear why tools like JSON formatters, validators, compressors, beautifiers, and escapers are useful.