JSON · JavaScript Object Notation
/ JAY-sahn /
JSON is a simple text format for writing down structured data — names paired with values — in a way that both people and programs can read. If you've ever seen { "name": "Ada", "age": 36 }, that's JSON: curly braces holding a list of keys and their values.
It's the lingua franca of APIs. When one program asks another for data over the web, the answer almost always comes back as JSON, because nearly every language can read and write it effortlessly.
The building blocks are tiny: text in "quotes", numbers, true/false, lists in [square brackets], and objects in {curly braces}. That's the whole language — small enough to learn in an afternoon, flexible enough to carry almost anything.
{
"name": "Ada",
"age": 36,
"languages": ["English", "Math"],
"active": true
}A whole person in four lines: text, a number, a list, and a true/false.
The name says 'JavaScript', but JSON is language-neutral — Python, Go, Rust and friends all speak it fluently.