lookup> .json

.JSON·File Extension

JSON Data File — Lightweight data-interchange format using key-value pairs, arrays and nested objects.

Data & Textapplication/jsonUTF-8Compressible

Quick facts

Extension.json

File typeJSON Data File

MIME typeapplication/json

CategoryData & Text

CharsetUTF-8

CompressibleYes

Format familyjson

What is .json

What is a .json file?

A .json file is a JSON Data File — Lightweight data-interchange format using key-value pairs, arrays and nested objects.

In the mime-db registry it maps to application/json with UTF-8 encoding, and it is marked as compressible. When serving .json over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to application/json and is used by JSON, OASv2-json among others — and is delivered over HTTP via the Content-Type header.

How to open .json files

Use VS Code or jq to open and edit .json files.
Any text editor (Notepad, VS Code) can inspect the raw content as text.

Developer info

When served over HTTP, responses should set the following header:

Content-Type: application/json; charset=utf-8

Common software that reads/writes .json:

VS CodejqPostmanPython

Relation chain

.jsonextension of

format

jsonserved as

mime type

application/jsonsent via header

http header

Related extensions

JSON5 Configuration File

Related MIME types

Related programming languages

JSON

.json .4DForm .4DProject

Common uses

API request and response payloads
Configuration files (package.json, tsconfig.json)
Data interchange between systems
NoSQL document storage

How to edit .json files

Open the file with VS Code, make your changes and save.
Most editors preserve the original formatting and encoding — avoid changing the charset.

How to create .json files

Create a new file and save it with the .json extension, or export this format from VS Code.

Example

{
  "name": "John",
  "age": 30,
  "active": true
}

Object — a collection of key/value pairs
Property — the key of a pair
String / Number / Boolean — JSON data types

Frequently asked questions

What programs can open .json files?

Common options include VS Code, jq, Postman. You can also open many of these files with built-in viewers or a browser.

How do I create a .json file?

Create a new file in any text editor or the app that owns the format and save it with the .json extension.

What is the relationship between .json and the application/json MIME type?

application/json is the media type identifier used for .json files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-08-18

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