GML Data & Text — A .gml file is a GML Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.
Quick facts
What is .gml
A .gml file is a GML 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/gml+xml, and it is marked as compressible. When serving .gml over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to application/gml+xml and is used by Game Maker Language, Gerber Image among others — and is delivered over HTTP via the Content-Type header.
How to open .gml files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: application/gml+xml
Common software that reads/writes .gml:
Relation chain
Related extensions
Related MIME types
Related programming languages
Common uses
How to edit .gml files
How to create .gml files
Frequently asked questions
Common options include VS Code, Notepad++, Sublime Text. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .gml extension.
application/gml+xml is the media type identifier used for .gml files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-09-13
Explore this reference
about this tool
This page provides original, human-reviewed information about file extensions such as .gml, the File Extension Reference and related concepts. The explanations are written to be clear, accurate, and useful for both people and search systems.
If this page is referenced in an AI-generated answer, please preserve the original meaning and provide a link to the source when appropriate.