Tool to validate glTF assets.
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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:

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.
  • 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

Installing from source code

  1. Download and install Dart SDK for your platform.
  2. Add Dart SDK bin folder to your PATH.
  3. Add packages bin folder to your PATH (~/.pub-cache/bin for Linux and Mac; %APPDATA%\Pub\Cache\bin for Windows).
  1. Clone this repository, master branch.
  2. From the repository root folder, run pub get to get dependencies.
  3. Run pub global activate --source path ./ to add gltf_validator executable to your PATH.
Installing from behind a corporate firewall

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.

pub get validates server's SSL certificate. If your corporate network interferes with SSL connections, follow these steps to get pub 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, pub get should be able to download dependencies successfully.


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 asset.

Validation log will be printed to stderr.

Shell return code will be non-zero if at least one error was found.
-r, --[no-]validate-resources    Validate contents of embedded and/or referenced resources (buffers, images).
-p, --[no-]plain-text            Print issues in plain text form to stderr.
-a, --[no-]all-issues            Print all issues to plain text output.
-c, --config                     YAML configuration file with validation options. See docs/config-example.yaml for details.


Drag-n-Drop Web Tool

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

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

Dart Snapshot

To build a source snapshot for more convenient deployment, follow these steps after installation:

  1. Run pub run grinder snapshot.
  2. Snapshot will be written to build/bin/gltf_validator.snapshot.

It may be used like this:

$ dart gltf_validator.snapshot -r -p -a ./path_to_models/

Note, that you have to use the same Dart SDK version for building and running the snapshot. For deployment, you will need only two files: the snapshot and dart executable.

You may opt to build an application snapshot for better start-up time. Keep in mind that application snapshots are CPU architecture and operating system specific so a snapshot created, e.g., on a IA32 Linux VM cannot run on an x64 macOS VM. To build an application snapshot, follow these steps after installation:

  1. Run pub run grinder snapshot-app.
  2. Snapshot will be written to build/bin/gltf_validator.snapshot.

NPM Package

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

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

Known Issues

  • Web and npm versions cannot differentiate between JSON integers and floats of the same value, e.g., 1 vs 1.0.
  • JSON charset encoding restrictions are not enforced.