What is a JSON file?
JSON — structured data
What is it?
JSON is the data-interchange format of the web. It doesn't describe a document but a structure: name/value pairs, lists, nested objects. It's what flows between an application and its server, millions of times a second across the globe.
Its syntax is minimal — braces, brackets, quotation marks — and stays readable by a human, which is unusual for a machine format.
History & origin
Douglas Crockford formalized JSON in the early 2000s, simply by codifying the way the JavaScript language declares its objects. He didn't invent anything: he named and documented something that already existed.
That simplicity won out over XML, dominant at the time: within a few years, nearly every web interface had switched to JSON.
Why it is useful
Lightweight, readable, universal: every programming language can read and write it without needing some obscure library.
It handles nested structures naturally, whereas CSV is hopelessly limited to a flat table.
Limits & drawbacks
No comments are allowed — a gap regularly cursed by those who use it for configuration files.
No date types, no comments, and an unforgiving syntax: one stray comma and the whole file becomes invalid.
Practical tips
To turn JSON data into a table you can work with in a spreadsheet, convert it to CSV — provided the structure is flat. Nested objects don't fit into columns.
For a configuration file that humans will be editing, YAML or TOML are more pleasant to work with: they allow comments.
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