GLB File Format (.glb)

A GLB file is glTF's binary packaging, developed by the Khronos Group, wrapping the JSON scene description together with its geometry buffers and textures into one self-contained file instead of a JSON document with separate buffer and image files beside it.

.glb3D Models

GLB at a glance#

Full name	Binary glTF
File extension	.glb
Category	3D Models
Developer	Khronos Group
MIME types	model/gltf-binary
Compression	Varies from file to file
Specification	glTF 2.0
FileFlip support	FileFlip reads and writes this format

What a .glb file can hold#

These are the things a GLB file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.

Embedded metadata	Yes
Textures and materials	Yes
Skeletons and animation	Yes

Strengths and limitations of GLB#

What GLB does well

One file, so nothing goes missing when it's moved, emailed or uploaded
The format web viewers, AR platforms and game engines mean when they say they support glTF
Loads faster than JSON glTF for large scenes, since geometry sits in a binary chunk instead of base64-encoded text

Where GLB falls short

Editing the JSON inside a GLB means unpacking it first, since the file itself isn't plain text
Same material and animation limits as glTF, since GLB is only a container around the same data model
Compressed variants using Draco or meshopt need an importer that specifically supports that extension

Use GLB whenever a model has to be handed to a web viewer, AR app or game engine as a single upload.

Convert GLB back to glTF's JSON form only when something inside the file needs to be read or edited directly.

How to open a .glb file#

A .glb file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts GLB into a format your machine already opens, and it does it in the browser tab rather than on a server.

Platform	Programs that open it
Windows	3D Viewer, Blender
macOS	Blender
Linux	Blender
Android	Scene Viewer
Web	FileFlip, Babylon.js Sandbox, model-viewer

GLB questions people ask#

Can I open a GLB file directly on my phone?

Android's Scene Viewer opens a GLB file straight into an AR view without a separate app, since it's built to consume glTF's binary form directly. iOS's AR Quick Look expects USDZ instead, so a GLB usually needs converting first to view in AR on an iPhone.

What does GLB stand for?

GLB is short for binary glTF, the single-file packaging of the glTF format. It isn't a separate format from glTF, just the same JSON scene, buffers and textures bundled into one container.

Why is GLB smaller than glTF?

A .gltf file stores its binary buffer data as base64 text embedded in JSON when it isn't split into separate .bin files, which inflates size by roughly a third. GLB stores that same data as raw binary bytes in its own chunk, so it avoids that text-encoding overhead entirely.

Do GLB and glTF look the same when rendered?

Yes, GLB and glTF describe the identical data model, meshes, materials, animations and scene graph, so a compliant viewer renders them the same way. The only difference is packaging: one file versus a JSON document with separate buffers and textures.

Converting GLB files#

Convert GLB to another format

Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.