.stl MIME type
STL model3d models
model/stlTriangle meshes for 3D printing and CAD.
| MIME type | model/stl |
|---|---|
| Extensions | .stl |
| Also seen as | application/sla |
| Content-Type | model/stl |
| Compress in transit? | Yes — enable gzip or Brotli |
Good to know
- Apache's stock
mime.typesmaps.stltoapplication/vnd.ms-pki.stl— a Windows certificate trust list. Override it if you serve 3D files. - Binary STL has no signature: an 80-byte header, then a triangle count. ASCII STL starts with
solid, but so do some binary files, so check that the size is 84 + 50 × the triangle count. - STL stores geometry only — no units, colors or textures. Use 3MF or glTF when those matter.
Serve .stl files with the right type
The response header to send:
Content-Type: model/stl
Most servers pick the type from the file extension. If yours sends the wrong one, map it explicitly:
nginx (inside the types block in mime.types)
model/stl stl;
Apache (.htaccess or server config)
AddType model/stl .stl
Express
res.set("Content-Type", "model/stl");Python
import mimetypes
mimetypes.add_type("model/stl", ".stl")HTML file input
<input type="file" accept=".stl,model/stl">
Check it
See what a server sends for a file, and what type a local file really is by its contents:
curl -sI https://example.com/file.stl | grep -i '^content-type:' file --mime-type file.stl
Frequently asked questions
What is the MIME type for .stl files?
model/stl. You may also see application/sla, but model/stl is the one to send.
What Content-Type header should a .stl file be served with?
Content-Type: model/stl. It compresses well, so let the server apply gzip or Brotli.
Related types
Headers that go with it: Content-Type · Content-Disposition · X-Content-Type-Options