STL 3D Model — Triangle-mesh format used for 3D printing.
Quick facts
What is .stl
A .stl file is a STL 3D Model — Triangle-mesh format used for 3D printing.
In the mime-db registry it maps to model/stl. When serving .stl over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to model/stl and is used by STL among others — and is delivered over HTTP via the Content-Type header.
How to open .stl files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: model/stl
Common software that reads/writes .stl:
Relation chain
Related extensions
Related MIME types
Related programming languages
Common uses
How to edit .stl files
How to create .stl files
Frequently asked questions
Common options include Blender, Cura, PrusaSlicer. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .stl extension.
model/stl is the media type identifier used for .stl files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
Explore this reference