Viewers
Free Online STEP Viewer — No Upload
This is a free online STEP viewer that opens AP203/AP214/AP242 models directly in your browser. Parsing runs locally via WebAssembly (OCCT), so the file never leaves your device — no upload, no registration.
Drag files here, or click to browse
Supports STEP, STP
Choose fileRe-drop the file after changing; Draft is faster, Ultra shows finer edges.
Supports .step / .stp (AP203/214/242) · parsed locally (OCCT WASM); files are not uploaded · Toolbar: distance / angle / annotate / section / screenshot / share / embed
Works on mobile too — tap to pick a file, one-finger rotate, pinch to zoom
What is a STEP file?
STEP (Standard for the Exchange of Product model data, ISO 10303-21) is the neutral CAD format for exchanging solid models between systems like SolidWorks, CATIA, NX, Fusion 360 and FreeCAD. AP203 and AP214 are the most common protocols; AP242 adds PMI/MBD annotations.
How to open a STEP file online
Drag your .step or .stp file into the viewer below. Geometry is tessellated in your browser with OCCT compiled to WebAssembly — you can measure distance and angle, cut sections, explode assemblies and take screenshots. Nothing is uploaded; closing the tab discards everything.
Convert STEP files
FAQ
Is this STEP viewer really free?
Yes. Viewing and measuring STEP files locally in your browser is free; no registration is required.
Are my STEP files uploaded to a server?
No. Parsing and rendering run entirely in your browser memory via WebAssembly. You can verify this in the browser Network tab — no file bytes are transferred.
Which STEP protocols are supported?
AP203, AP214 and AP242 files are supported, including large assemblies. Parsing can be cancelled midway while keeping the last loaded model.