lookup> .gmx

.GMX·File Extension

GMX Data & Text — A .gmx file is a GMX Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.

Data & Textapplication/vnd.gmx

Quick facts

Extension.gmx

File typeGMX Data & Text

MIME typeapplication/vnd.gmx

CategoryData & Text

Charset—

Compressible—

What is .gmx

What is a .gmx file?

A .gmx file is a GMX Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.

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

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

How to open .gmx files

Use VS Code or Notepad++ to open and edit .gmx 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/vnd.gmx

Common software that reads/writes .gmx:

VS CodeNotepad++Sublime Textjq

Relation chain

.gmxextension of

format

GMX Data & Textserved as

mime type

application/vnd.gmxsent via header

http header

Related extensions

Related MIME types

Related programming languages

XML

.xml .adml .admx

Common uses

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

How to edit .gmx 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 .gmx files

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

Frequently asked questions

What programs can open .gmx files?

Common options include VS Code, Notepad++, Sublime Text. You can also open many of these files with built-in viewers or a browser.

How do I create a .gmx file?

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

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

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

Sources & standards

Updated 2026-08-18

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