What Is a .json5 File? .json5 Format, MIME & How to Open

Quick facts

Extension.json5

File typeJSON5 Configuration File

MIME typeapplication/json5

CategoryData & Text

Charset—

Compressible—

Format familyjson

What is .json5

What is a .json5 file?

A .json5 file is a JSON5 Configuration File — Relaxed JSON syntax allowing comments, trailing commas and unquoted keys.

In the mime-db registry it maps to application/json5. When serving .json5 over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to application/json5 and is used by JSON5 among others — and is delivered over HTTP via the Content-Type header.

How to open .json5 files

Use VS Code or Node.js to open and edit .json5 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/json5

Common software that reads/writes .json5:

VS CodeNode.js

Relation chain

.json5extension of

format

jsonserved as

mime type

application/json5sent via header

http header

Related extensions

Related MIME types

Related programming languages

JSON5

.json5

Common uses

Configuration files
Data interchange between systems
API request and response payloads
Logs and data exports

How to edit .json5 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 .json5 files

Create a new file and save it with the .json5 extension, or export this format from VS Code.

Frequently asked questions

What programs can open .json5 files?

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

How do I create a .json5 file?

Create a new file in any text editor or the app that owns the format and save it with the .json5 extension.

What is the relationship between .json5 and the application/json5 MIME type?

application/json5 is the media type identifier used for .json5 files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-08-18

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