What the extension does
- Badge on the toolbar icon: how many links to STL, OBJ, 3MF, STEP, IGES, GLB, PLY and G-code files the page has. A list opens any of them.
- Right-click a link → Open in STL Viewer: the file opens in a viewer tab.
- Toolbar button: opens an empty viewer for a file from your disk.
It suits model repositories, supplier portals and course pages that link many parts: you can check sizes and the mesh before keeping any of them. Everything after opening is the same viewer as on this site.
How the file travels
When you open a link, the extension downloads the file from the site that hosts it and passes it to the viewer tab inside your browser. The model does not go through our servers on the way. The extension is built on Manifest V3. The context menu adds the right-click items, and access to sites lets it read links on the page and fetch the file you clicked. The side panel lists the files of the current tab, your recent files and the settings. Downloads and notifications save one or all files and offer to open a 3D file you have just downloaded. Settings and the last 10 files you opened stay in this browser, and the extension records no browsing history.
Chromebooks and school laptops
Chromebooks run Chrome, which is the browser the extension is built for, so it is the natural route on machines where installing CAD software is impossible. We have tested the extension and the viewer in desktop Chrome; a Chromebook run is still on the list, so treat ChromeOS as expected to work rather than verified.
Students can open a classmate's STEP or 3MF straight from a shared page, measure it and convert it to STL for the lab printer.
Install
The extension is distributed through the Chrome Web Store. Until the store listing goes live, the site itself does everything except the link badge: drop the downloaded file on the STL viewer.
Contact
Problems with the extension or a link it does not pick up: support@stlview.app, with the address of the page.
Questions and answers
Is there a 3D viewer for Google Chrome that opens STEP?
Yes. The viewer behind this extension tessellates STEP and IGES in the tab with OpenCascade and shows the declared unit converted to millimetres.
Which file links does the badge count?
Links to STL, OBJ, 3MF, STEP, IGES, GLB, PLY and G-code files.
Why does it need access to sites?
To read the links on the page you are viewing and to download the file you choose. It records no browsing history and sends nothing to us.
Does it work in Edge?
Edge is a Chromium browser, the family the viewer is tested in. The extension has been tested in Chrome.