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Get the browser extension

A lighter, browser-integrated version of the converter: it watches your downloads and offers a one-click "Convert to STEP" whenever you download an .stl or .3mf file from any site — no need to open a tab and drag the file in yourself. Everything still runs 100% locally, exactly like the web converter.

Chrome

Version 1.0.0
⬇ Download for Chrome

Microsoft Edge

Version 1.0.0
⬇ Download for Edge

1. Unzip the download

The extension isn't in the Chrome Web Store or the Edge Add-ons store — it's distributed directly as a .zip so anyone can install and inspect it for free. Unzip it anywhere you like (double-click it on Mac, or right-click → "Extract All" on Windows). You'll get a folder — keep it where it is, the browser will keep loading the extension from that folder.

2. Load it into your browser

Chrome:

  1. Open chrome://extensions
  2. Turn on Developer mode (top-right toggle)
  3. Click Load unpacked
  4. Select the unzipped folder

Edge:

  1. Open edge://extensions
  2. Turn on Developer mode (toggle in the left sidebar)
  3. Click Load unpacked
  4. Select the unzipped folder

3. That's it

The converter's icon appears in your toolbar. From then on, downloading an .stl or .3mf from any site (or a .zip from a 3D-model site) pops up a notification with a "Convert to STEP" button. You can also click the toolbar icon any time to open the converter directly and drag a file in by hand.

Browsers show a "Developer mode" warning because unpacked extensions skip the store review process — that's expected here, not a sign of anything wrong. This build is open source: you can read every line before installing it, in the same public repository that powers this website. It asks for no account, sends nothing to any server, and works exactly like the web converter — just with automatic download detection built in.
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