Among others, the standard function set offered no integration or root-finding capabilities and lacked support of matrices and complex numbers, which could be added by an extension module.

Pyrex allows the user to write extension modules in a Python-like language which may directly access the external C code.

Development of provider module (extension module) based on the specifications is also possible with the SDK.

Next, a simple but relevant technology was the direct execution made on extension modules, started with SSI.

It can generate stand-alone programs or extension modules that can be imported and used in larger Python programs.

Note that any other module, such as pygame, pyqt or pickle, may be used in combination with a Shed Skin generated extension module.

It is possible to write extension modules using the Lua API.

Lua scripts may load extension modules using , just like modules written in Lua itself.

It is organised as a relatively small kernel which defines a standard software interface to which extension modules are required to conform.

These extension modules can then be loaded and used by regular Python code using the import statement.