---
title: "GLB/GLTF Validator"
description: "Validate GLB and GLTF files for container header, chunk layout, JSON structure, required fields, and common issues. All checks run locally in your browser."
toolId: "gltf-validator"
category: "analysis"
subgroup: "model-info"
subgroupName: "Model Analysis"
url: "https://any3d.cc/en-US/tools/gltf-validator"
markdown: "https://any3d.cc/llm/tools/gltf-validator.md"
---

# GLB/GLTF Validator

Check GLB / GLTF files for header, chunk and JSON structure and common issues, fully local.

**Category:** 3D Model Analysis Tools (`analysis`)
**Subgroup:** Model Analysis (`model-info`)

**HTML:** https://any3d.cc/en-US/tools/gltf-validator

> Runs entirely in the browser. Files are not uploaded to Any3D servers.

## Overview

Upload a GLB or GLTF file and the tool checks the container header, chunk layout and JSON structure against the glTF 2.0 specification. GLTF files may reference external .bin buffers and textures; upload them together. Results are shown immediately; nothing is uploaded to a server.

## Tips

- Validation happens in your browser, with no upload
- Supports GLB and GLTF (including external .bin)
- Every problem gets its own fix suggestion

## About Configuration Options

### Result Severity Levels

- **Error**: The file has structural defects that may break viewing or conversion.
- **Warning**: A potential issue was found; verify before use.
- **Note**: Normal structural information about the file.

### GLB/GLTF Checks

- **Magic number**: The header must start with the glTF magic 0x46546C67.
- **Version**: GLB version; the current glTF 2.0 spec version is 2.
- **Total length**: The total length declared in the header must match the actual byte count.
- **Chunk layout**: A JSON chunk is required and must come before the BIN chunk.
- **JSON structure**: Required fields and reference integrity of the glTF document.
- **Minimum size**: A GLB must be at least 20 bytes; smaller files are truncated or empty.
- **BIN chunk**: The binary chunk carries geometry data; its bounds must fit the declared length.
- **asset.version**: The JSON chunk must declare asset.version (glTF 2.0).

## Format Information

### Input format

- **Extension:** glb
- **Full Name:** GL Transmission Format Binary (glTF 2.0)
- **Type:** 3D Model
- **Format:** GLB
- **Tools:** [Three.js](https://threejs.org), [Babylon.js](https://www.babylonjs.com), [Blender](https://www.blender.org)
- **Open With:** [3D Model Viewer](https://any3d.cc/en-US/tools/3dmodel-viewer), [GLB Viewer](https://any3d.cc/en-US/tools/glb-viewer)
- **Description:** GLB is the binary glTF 2.0 format from Khronos Group, packing meshes, materials, textures, and animations into one file. It is the standard for Web 3D and AR/VR, used by Three.js, Babylon.js, model-viewer, and e-commerce previews for self-contained, reliable distribution.

GLB supports PBR materials, skeletal animations, Draco and Meshopt compression, suitable for web, AR, and cross-software use. However, it loses CAD parametric history when tessellated from STEP or native CAD. For 3D printing, use STL or 3MF as slicers cannot import GLB.
- **Supported Features:**
  - Single self-contained binary file
  - PBR material support (base color, metallic, roughness, normal maps)
  - Skeletal animation, skinning, and morph targets
  - Draco mesh compression and KTX2 texture compression
  - Multi-mesh nodes and scene hierarchy
- **Notes:**
  - Some 3D printing slicers cannot directly import GLB files
  - Not suitable for CAD parametric editing

## How to use

### 1. Upload a file

Drop a GLB or GLTF file

### 2. Review results

See magic, version, chunk and JSON details

### 3. Fix if needed

Re-export a valid GLB or glTF from your DCC tool

## FAQ

### How are GLB and GLTF files checked differently?

GLB is a single binary container that bundles the JSON, buffers and textures into one file. GLTF is a JSON file that may reference external .bin and texture files. Upload them together for a full check.

### Can external GLTF files be checked?

Yes. External .bin buffers and textures referenced by GLTF can be uploaded together; the tool checks the integrity of these references.

### How strictly is the glTF JSON validated?

The JSON is parsed against the glTF 2.0 specification: required fields such as asset.version and meshes, buffer and image references, and bufferView/accessor bounds are checked. GLB files additionally get their magic number, version, total length and chunk layout verified. EXT_ or vendor extensions are not interpreted.

### My GLTF fails validation: what is usually wrong?

The most common causes are invalid JSON, missing required fields such as asset.version, external .bin or texture files not uploaded together with the .gltf, and buffer references that point outside their data. Re-export the file as glTF 2.0 from your DCC tool. The report names the exact field or chunk that failed.

### Will the validator repair issues in my file?

No. Validation is read-only: neither the GLB binary chunks nor the glTF JSON document are modified. Issues are fixed by re-exporting the file from your DCC tool.

### Will a file that passes validation always load?

Structural checks rule out common problems in the header, chunks and required JSON fields. Special extensions or business fields required by particular applications are not covered.

### Is Any3D completely free?

Yes, Any3D's core features are free to use forever. We provide format conversion, model optimization, and online preview at no cost, with no registration required.

### Are my files uploaded to your servers?

No. Files you select are processed only in your browser on this device, so they never leave your device and are never sent to our servers. We don't store any user files; after processing, related data in browser memory is released.

### Do I need to install software?

No installation required. Any3D is entirely browser-based; just open the webpage to use all features. It works on Windows, Mac, Linux, and other major operating systems.

### Is there a file size limit?

The processing capacity depends on your device performance and the model's vertex count and texture complexity, rather than file size alone. We impose no file size limit, but when a model exceeds what your device can handle, the page may lag or even crash.