GLB vs glTF: the same format in two containers
GLB and glTF are the same Khronos format in two containers. The choice is about delivery, not fidelity: .gltf describes the asset in JSON, while a self-contained .glb packages it into one binary file. Compression is a separate decision.
The short answer
GLB and glTF describe the same format with different packaging. Choose by delivery and editing workflow, rather than assuming one container has better fidelity.
What glTF actually is: JSON, buffers and textures
A .gltf file describes the scene in JSON, with buffers and textures that may be separate resources or embedded data.
What GLB changes: a 12-byte header and one file
GLB packages JSON and binary content in a binary container with a 12-byte header. A self-contained export is convenient to distribute as one file.
The comparison table
Separate .gltf keeps JSON readable and textures easy to replace. Embedded .gltf keeps data in JSON with base64 overhead. A self-contained .glb packages the asset for upload and sharing.
| Delivery | Separate .gltf | Embedded .gltf | Self-contained .glb |
|---|---|---|---|
| Resources | JSON, buffers and textures | JSON with embedded data | One binary container |
| Inspecting JSON | Directly readable | Readable alongside encoded data | Extract JSON chunk first |
| Replacing textures | Separate texture files | Update embedded data | Repackage the container |
| Delivery concern | Keep resource paths intact | Base64 adds size overhead | Convenient upload and sharing |
When to use .gltf
Use .gltf when inspecting JSON or changing separate textures is useful. Keep referenced buffers and textures available at their expected paths.
When to use .glb
Use a self-contained .glb for a delivery workflow that benefits from one file. Container choice alone does not reduce the work of rendering its contents.
Compression and extensions: Draco, Meshopt and KTX2
Draco, Meshopt and KTX2 change the decoder requirements. Confirm extension support in the target viewer before distributing the compressed asset.
Other formats you will meet, and when not to use them
OBJ, STL, FBX and USDZ serve different workflows. Geometry exchange, animation and delivery to a browser are different requirements; choose for the receiving tool.
FAQ
glTF vs GLB: is there a quality difference?
Packaging alone does not change the meshes, materials or animations; compression and export settings are separate decisions.