GLB and glTF viewer online — open .glb files in the browser, Draco included

A GLB file is the binary, single-file form of glTF — the Khronos Group’s modern 3D transmission format, the one that comes out of Blender exports, Sketchfab downloads, Apple’s AR Quick Look, and effectively every game engine. A .glb packs geometry, PBR materials, and textures into one file; a .gltf is the same data in JSON, often with images alongside. Loft opens both in the browser, materials intact, with no app and no upload.

What GLB and glTF actually are

glTF stands for “GL Transmission Format.” Khronos designed it as the JPEG of 3D — a runtime-ready format meant to be loaded and drawn, not authored and re-authored. That focus is why it carries physically-based-rendering (PBR) materials, full node hierarchies, and texture references in a layout a renderer can consume directly.

The two extensions you’ll meet are .gltf and .glb. A .gltf is human-readable JSON that usually points at external .bin geometry and image files. A .glb is the binary container: the same JSON, the geometry buffers, and the embedded textures fused into one self-contained file. GLB travels better, which is why most downloads you encounter in 2026 are .glb.

Who needs to open one — and the usual pain

You downloaded an asset from Sketchfab, a teammate dropped a .glb in Slack, a client sent the AR model for their product page, or Blender just spat one out and you want to confirm it exported cleanly. None of that should require installing Blender, signing into a 3D-asset SaaS, or uploading the file to a stranger’s “free online viewer.”

The friction is real. Desktop 3D suites are heavy installs with a learning curve. Most browser viewers that handle GLB quietly POST your file to a server first. And if the model is a paid asset or unreleased product geometry, “upload to inspect” is exactly the step you don’t want to take.

How Loft’s viewer handles it

Drop a .glb or .gltf and the viewer parses it and renders it in a Three.js WebGL2 orbit scene, preserving the PBR materials and textures as authored — so the model looks the way it did in Blender or wherever it came from. Drag to orbit, right-click drag (or two-finger drag on a trackpad) to pan, scroll to zoom. A reset-camera button frames the model in one click when you lose it off-screen.

All of Loft’s mesh viewers — GLB, STL, OBJ, PLY, 3MF — share a single WebGL viewer core, so the controls are identical whichever format you land on. Toggle between shaded and wireframe modes to inspect topology, and the status footer reports triangle count and file size so you can sanity-check how heavy an asset really is. There’s a point-to-point measurement tool too: click two surface points and the distance shows in the model’s native units, and because it works recursively across a multi-mesh model, you can measure between separate parts. When the view looks right, Screenshot exports the textured render — materials and lighting baked in — as a PNG.

The Draco part, demystified

Draco is Google’s open-source mesh-compression library. A lot of GLBs in the wild, especially anything tuned for the web or AR, ship their geometry Draco-compressed to cut the download — sometimes dramatically. The catch is that a viewer has to decode Draco before it can draw anything, and plenty of basic viewers simply can’t, so the model shows up empty or throws an error.

Loft wires the Draco WASM decoder in automatically. You don’t toggle a setting or convert the file first — drop the compressed .glb and it decompresses in your browser, on your machine, then renders. “Draco” is the one term worth knowing here; if a model ever refuses to open elsewhere, search whether it’s Draco-compressed and that’s usually your answer.

Nothing leaves your device

This is the part that matters most and gets the least airtime elsewhere. Parsing and rendering happen entirely in your browser tab. The .glb is never uploaded — there is no server round-trip, because the WebGL renderer and the Draco decoder that read the file are already running on your machine. (For the longer version of why in-browser compute removes the upload step, see how it works.)

For an unreleased product model, a paid marketplace asset, or anything under NDA, that’s the difference between “I inspected it” and “I uploaded it to a service whose privacy policy I didn’t read.” After the first visit the viewer is cached and works offline, so you can open a GLB on a plane with no signal — the file would have nowhere to go even if the tool wanted to send it.

Honest limits

The viewer is read-only. It won’t let you edit the model — no re-texturing, no moving nodes, no re-exporting. It’s built to open, inspect, measure, and screenshot, and then you take what you learned back to your authoring tool. If you need to change the asset, this isn’t that; Blender is.

A few more sharp edges worth stating plainly. If your GLB carries animations, they don’t play in this release — the focus is static geometry inspection, and animation playback is on the roadmap, not in the build today. (Full disclosure: an early draft of the tool’s own copy oversold this, and I’d rather you hear the accurate version here than be surprised by a model that sits still.) And a .gltf that references external image files won’t show those textures unless the images come along — which is the everyday case for preferring .glb, where everything is embedded in one file. If a model loads dark, it’s usually the camera sitting inside the geometry; hit Reset view first.

Works wherever your browser does

Because the whole thing runs on WebGL2 in the tab, it’s the same tool on Windows, macOS, Linux, ChromeOS, and — usefully — on a phone or tablet. No “desktop only” wall. The 100 MB ceiling per file covers the overwhelming majority of GLBs you’ll actually be handed; genuinely massive scene exports are the exception, and very dense meshes may pause briefly while they parse, which is a local compute cost, not an upload.

If you also work in other mesh formats, the sibling viewers behave identically — the STL viewer for 3D-printing models is the same core with a different default, and there’s a walkthrough of running a CAD viewer on a phone if you’re curious how browser-side 3D holds up on constrained devices.

Takeaway

GLB is the format the 3D web converged on, and checking one shouldn’t cost you an install or an upload. Drop your file into the GLB / glTF Viewer, let it decompress Draco and render the materials, orbit around, measure what you need, and grab a screenshot — all in the tab, none of it leaving your machine.