Open STEP files online
STEP and IGES are the standard formats for exchanging precise solid CAD models between engineering tools. The viewer tessellates the model with OpenCascade (WebAssembly) and shows it in an interactive 3D view — drag to orbit.
Drop a STEP file to open it
or click to choose — everything stays on your device
Choose file🔒 100% private — files never leave your browser
You can also edit STEP online — change the content with find & replace, then save it back. Nothing is uploaded. Or turn STEP into an image — snapshot the preview, add arrows or notes, and download a PNG.
What is a STEP file?
STEP and IGES are the standard formats for exchanging precise solid CAD models between engineering tools. The viewer tessellates the model with OpenCascade (WebAssembly) and shows it in an interactive 3D view — drag to orbit. The .STEP extension identifies a STEP / IGES CAD model file, which is served with the application/step media type. You can open it here instantly — drop the file into the box above and it renders in your browser. Nothing is uploaded.
Besides this free online viewer, you can open STEP / IGES files in desktop apps such as FreeCAD, SolidWorks, Fusion 360 — but here all you need is a web browser.
Quick facts
| Format | STEP / IGES — STEP / IGES CAD model |
|---|---|
| File extensions | .step .stp .iges .igs |
| MIME type | application/step |
| Developer | ISO |
| Category | 3D, CAD & GIS |
| Also opens in | FreeCAD, SolidWorks, Fusion 360 |
How to open a STEP file online
- Click Choose file above, or drag your STEP file onto the box.
- The right viewer loads automatically and renders your file.
- Read, scroll or page through it. To open a different file, choose Open another file.
100% private — files never leave your browser.
Libraries used to render STEP in the browser
This viewer is built entirely with open-source JavaScript that runs in your browser:
Frequently asked questions
What is a .STEP file?
A .STEP file is a STEP / IGES CAD model, identified by the application/step media type. You can open and read it instantly in the viewer above without installing anything.
What programs open STEP files?
On the desktop, STEP files typically open in FreeCAD, SolidWorks, Fusion 360. Online, this page opens them in any modern browser — nothing to download.
Can I edit a STEP file online?
Yes. Open your file, switch to Edit, change the text with built-in find & replace, then click Save. It all runs in your browser — nothing is uploaded.
How do I convert STEP to an image?
Use Snapshot to capture the STEP preview, optionally add arrows, text or highlights, then download it as a PNG image.
Is it safe to open my STEP file here?
Yes. The file is read and rendered entirely by JavaScript inside your own browser. It is never uploaded to a server, so nothing leaves your device.
Do I need to install anything to view a STEP file?
No. There is nothing to install and no account to create. Open the page, drop your file, and it displays instantly.
Does it work on my phone or iPad?
Yes. The viewer is fully responsive and works in modern mobile and tablet browsers such as Safari and Chrome.
Is there a file size limit?
There is no hard limit, but very large files depend on your device’s memory. Big files are processed in the background so the page stays responsive.