Free Online glTF Validator
Check the structure, resources, and consistency of a GLB or glTF asset with the Khronos glTF Validator. Real results, right in your browser.
Good models start with a good check.
Drop a GLB or glTF file and its resources here.
Runs on your device · Up to 100 MB · No WebGL requiredWhat the check tells you
The validator checks your asset against the glTF specification, including accessor bounds, buffer references, scene structure, and supported extension rules. Issues include a severity, an error code, and a JSON pointer when available.
For a .gltf model, include every referenced BIN and image file. The validator reports missing resources; it does not silently fetch them from remote servers. Unknown extensions may receive a warning because the validator cannot check every extension.
How to use the results
- Open each issue to read the explanation and JSON pointer.
- Fix the export or source asset in your 3D application.
- Export again and run a fresh check.
- Open the asset in the 3D viewer and your target application.
Validation checks data. It does not prove that your model will render identically in all software, and this tool does not automatically repair errors.
What a glTF validation report contains
The Khronos validator analyzes the selected glTF 2.0 document and the local resources supplied with it. A result can include errors, warnings, informational messages, and hints. Each issue has a code and explanation; when the source data has a precise location, the report includes a JSON Pointer to help you find the affected field. The downloadable JSON preserves structured results for a teammate or a later comparison. The report also identifies the validator version used for the check.
An error usually means the checked asset violates a rule or contains data the validator cannot accept. A warning points to a concern that may affect portability or correctness without necessarily preventing a preview. Informational messages and hints provide additional context. Read the issue itself rather than treating every nonzero count as the same severity.
Prepare the complete package
For a binary .glb, select the file and any external resources it names. For a JSON .gltf file, select the root document together with every referenced buffer and image. Relative paths and letter casing matter: if the document requests textures/wood.png, selecting a different file named wood.jpg does not resolve that reference. Folder selection is useful when nested paths or duplicate filenames are involved.
This browser validator reads the selected files locally. It does not fetch remote URIs from the model or upload the asset to a validation service. If a dependency is missing, the report may identify the unresolved URI; return to the source package and obtain that exact resource from a trusted location.
Use validation alongside a visual review
Validation and rendering answer different questions. A structurally valid file can still have unexpected materials, an incorrect scale, or an animation that does not suit its destination. A viewer may also fail to render an asset whose malformed JSON or buffer problems the validator can still identify. Run the check, preview the scene, then open it in the application where it will be used.
For repairs, keep the original project, fix the source or exporter setting, and create a new file. Run validation again and compare the issue codes. The tool reports findings but does not rewrite the asset; visual appearance and runtime compatibility still need to be checked in their respective applications.
Common validation problems
Missing buffers and images often come from moving only the .gltf document, flattening a folder, or changing a filename after export. Invalid JSON can result from a damaged download or an incorrectly edited document. Buffer and accessor issues can point to mismatched byte lengths, offsets, or declared bounds. Extension messages indicate that an asset uses an optional feature; check whether it is required and whether the target renderer supports it.
When the message is unclear, use its JSON Pointer to inspect the source value, then check the exporting application's settings. Avoid editing binary offsets by hand unless you understand the file layout. Re-exporting from the source project is usually easier to verify than patching a damaged package.
Limits and next steps
The default total selection limit is 100 MB. A validation run can be cancelled, stops after its configured time limit, and caps the number of displayed issues so a malformed file cannot create an unbounded report. Large inputs also depend on available browser memory. If the browser cannot process a file, try a local desktop validator or reduce the asset in its authoring tool.
Use the glTF file guide when you need help preserving external resources, or open a model in the GLB viewer after the check. The official Khronos glTF Validator project documents the validation engine and its source.
Frequently asked questions
Does this use the real Khronos validator?
Yes. Checks run using the gltf-validator package from Khronos in a browser worker. The report includes its validator version and original issue codes.
Can I validate a model that does not render?
Yes. This page does not require WebGL or a successful 3D preview. Invalid JSON or a broken GLB may produce validation errors even when the viewer cannot open it.
Are my validation files private?
Selected files and their resources are read on your device. No model data is sent to our server. The downloadable JSON report can include the local file name, so review it before sharing.
What are the limits?
The default total selection limit is 100 MB. Validation stops after 60 seconds and reports up to 2,000 issues. You can cancel a running check.
Specification and engine: KhronosGroup/glTF-Validator.