Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Failed to load latest commit information.
Latest commit message
Commit time


Build Status

Tool to validate glTF assets.

Validation is performed against glTF 2.0 specification.

Validator writes a validation report (in JSON-format) with all found issues and asset stats.

Live drag-n-drop tool:

NPM package:

NuGet package [Third-party contribution]:

Implemented features

  • JSON syntax check and GLBv2 file format correctness.
  • Asset description validation
    • All properties and their types from JSON-Schemas (including implicit limitations on valid values).
    • Validity and compatibility of internal references.
    • Correctness of Data URI encoding.
  • Binary buffers validation
    • Forbidden or incorrect accessor values (e.g., NaN, invalid quaternions, indecomposable matrices, etc).
    • accessor.min and accessor.max values.
    • Sparse accessors encoding.
    • Animation inputs and outputs.
  • Images validation
    • Warning on non-power-of-two dimensions.
    • Warning on unsupported image features (like animations or custom color spaces).
  • Extensions validation
    • EXT_texture_webp
    • KHR_lights_punctual
    • KHR_materials_clearcoat
    • KHR_materials_emissive_strength
    • KHR_materials_ior
    • KHR_materials_iridescence
    • KHR_materials_pbrSpecularGlossiness
    • KHR_materials_sheen
    • KHR_materials_specular
    • KHR_materials_transmission
    • KHR_materials_unlit
    • KHR_materials_variants
    • KHR_materials_volume
    • KHR_mesh_quantization
    • KHR_texture_transform
  • Full list of detectable issues.


You can use hosted web front-end tool. It works completely in the browser without any server-side processing.

Command Line Tool Usage

Usage: gltf_validator [<options>] <input>

Validation report will be written to `<asset_filename>.report.json`.
If <input> is a directory, validation reports will be recursively created for each *.gltf or *.glb asset.

Validation log will be printed to stderr.

Shell return code will be non-zero if at least one error was found.
-o, --[no-]stdout                Print JSON report to stdout instead of writing it to a file. This option cannot be used with directory input.
-r, --[no-]validate-resources    Validate contents of embedded and/or referenced resources (buffers, images).
                                 (defaults to on)
-t, --[no-]write-timestamp       Write UTC timestamp to the validation report.
-p, --[no-]absolute-path         Write absolute asset path to the validation report.
-m, --[no-]messages              Print issue messages to stderr. Otherwise, only total number of issues will be printed.
-a, --[no-]all                   Print all issue messages to stderr. Otherwise, only errors will be printed. Implies --messages.
-c, --config                     YAML configuration file with validation options. See docs/config-example.yaml for details.
-h, --threads                    The number of threads for directory validation. Set to 0 (default) for auto selection.



  1. Download and install Dart SDK for your platform.
  2. Add Dart SDK bin folder to your PATH.
  3. From the repository root folder, run dart pub get to get dependencies.

Fetching dependencies from behind a corporate firewall

dart pub get downloads dependencies from Google's server over HTTPS. If you need to specify a proxy, follow these steps:

  1. Set https_proxy or HTTPS_PROXY environment variable in form hostname:port.
  2. If the proxy requires credentials, use this syntax: username:password@hostname:port.

dart pub get validates server's SSL certificate. If your corporate network interferes with SSL connections, follow these steps to get it running.

  1. Save your corporate self-signed root certificate as X.509 file.
  2. (Linux only) Try to add your cert to /etc/pki/tls/certs/ca-bundle.crt or /etc/ssl/certs.
  3. If that doesn't work or if you're on Windows, add environment variable DART_VM_OPTIONS with value --root-certs-file=<cert_file>.

After doing this, dart pub get should be able to download dependencies successfully.

Drag-n-Drop Web Tool

To build a drag-n-drop online validation tool (as hosted here), follow these steps after installation:

  1. Run dart run grinder web.
  2. All needed files will be written to build/web directory.

CLI tool

  1. Run dart run grinder exe.
  2. Native executable file will be written to build/bin/gltf_validator or build/bin/gltf_validator.exe.

NPM Package

To build an npm package for use in Node.js environment, follow these steps after installation:

  1. Run dart run grinder npm.
  2. gltf-validator npm package will be written to build/node.

Refer to the npm package documentation for additional information.


To publish an npm package, follow these steps after installation:

  1. Run dart run grinder npm-publish.
  2. gltf-validator npm package will be built to build/node and published to npm registry using npm publish.

Validation Issues List

To generate, follow these steps after installation:

  1. Run dart run grinder issues.
  2. file will be written to the repo root.