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JSON

A lightweight data-interchange format, not a programming language but ubiquitous in APIs.

data format

Quick facts

NameJSON

Aliasesgeojson, jsonl, sarif, topojson

Typedata format

Extensions.json .4DForm .4DProject .avsc .geojson .gltf .har .ice

MIME type—

What is JSON

JSON

A lightweight data-interchange format, not a programming language but ubiquitous in APIs.

GitHub Linguist classifies JSON as a data format, typically using extensions such as .json, .4DForm, .4DProject, .avsc, .geojson, .gltf.

File extensions:

.json.4DForm.4DProject.avsc.geojson.gltf.har.ice.JSON-tmLanguage.json.example.jsonl.mcmeta

Related extensions

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Frequently asked questions

What is JSON mainly used for?

A lightweight data-interchange format, not a programming language but ubiquitous in APIs.

Which file extensions does JSON use?

Common extensions include .json, .4DForm, .4DProject, .avsc, .geojson.

Sources & standards

Updated 2026-08-18

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