What is a .gltf file? (glTF)

glTF is the modern, open standard for 3D on the web, often called the JPEG of 3D. It is compact and fast to load, carrying meshes, materials, textures and animation, and it renders directly in browsers and AR viewers.

What is a .gltf file used for?

glTF was designed for efficient delivery and quick rendering. The text .gltf form is JSON, while the binary .glb packs everything, including textures, into one file.

It supports physically based materials and animation, so a single glTF can present a fully shaded, moving model in a browser without plugins.

It is now the preferred web and AR format, with strong support in engines, viewers and phones.

How to open a .gltf file

The .gltf format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list. For a step-by-step walkthrough, see how to open a .gltf file.

Windows

Windows 3D Viewer
Blender
Babylon.js Sandbox (web)

macOS

Preview (some)
Blender
web viewers

Linux

Blender
web viewers

Web

Browsers via WebGL viewers

How to convert a .gltf file

You can convert a .gltf file to OBJ, FBX, STL using a conversion tool or the export menu of an app that opens it.

.gltf file signature (magic bytes)

Programs recognise a .gltf file by the bytes at the start of the file, not by its name. These are the signatures for glTF. For a full breakdown, see the glTF file signature page.

Hex signature	Offset	Note
67 6C 54 46	0	'glTF' (binary .glb)
7B	0	'{' (text .gltf is JSON)

See the full magic-numbers reference for every format.

Frequently asked questions

What is a .gltf file?

What is the difference between glTF and GLB?

They are the same format. .gltf is the text (JSON) version with separate asset files, .glb packs everything into one binary file.

Related formats

Sources

Details on this page were checked against authoritative references:

Wikipedia: glTF