JSON is a lightweight data format used by virtually every web API, configuration file, and NoSQL database to move structured data between systems. The language APIs speak. Every time your browser fetches data from a server — a weather forecast, a social-media feed, a search result — the response almost certainly arrives as JSON. It stands for JavaScript Object Notation, but calling it a JavaScript format undersells its reach. JSON is language-independent, human-readable, and so minimal it can be explained in a single index card: curly braces for objects, square brackets for arrays, key-value pairs separated by colons. Douglas Crockford didn't invent it so much as discover it — the syntax was already sitting inside JavaScript, waiting for someone to write down the rules.
Technical details
Full Name
JavaScript Object Notation
MIME Type
application/json
Developer
Douglas Crockford
Magic Bytes
N/A
Safety
.json is a known, safe format.
What opens it
Any text editor
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VS Code
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Firefox (formatted view)
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FAQ
What is the difference between JSON and XML?
JSON is lighter — less syntax, smaller files, faster parsing. XML is more verbose but supports attributes, namespaces, and schemas. JSON won the web because it’s simpler and maps naturally to JavaScript objects. XML still dominates in enterprise systems, SOAP APIs, and document formats like DOCX.
How do I open or read a JSON file?
Any text editor works. VS Code gives you syntax highlighting and formatting. Firefox displays JSON files with a built-in formatted viewer. For large files, use a dedicated tool like jq (command line) or an online JSON viewer.
What is the difference between JSON and YAML?
YAML uses indentation instead of braces and is designed to be more human-readable. JSON is stricter and more machine-friendly. YAML is popular for configuration files (Docker Compose, Kubernetes). JSON is the standard for APIs and data exchange. YAML is a superset of JSON — valid JSON is valid YAML.
Can JSON contain comments?
Standard JSON does not support comments. This is by design — Crockford excluded them to prevent misuse as parsing directives. If you need comments, use JSONC (JSON with Comments, supported by VS Code), JSON5, or switch to YAML or TOML for config files.