Start coding for Blender

Blender core is coded in C. Some part like Cycles are coded in C++. Python is widely used for extending Blender functionalities with scripts and addons.

(For BlenderBIM Addon specific code see BlenderBIM Add-on code examples)

C/C++

Blender foundation made a video to present code structure :

Dive Into The Code (peertube)

python

Introduction

Good introduction to python use in Blender from Curtis Holt :

To learn more checkout the Blender Python API documentation especially Quickstart part.

Tips and Tricks

Blender Python API documentation has a special Tips and Tricks chapter including external editor usage, inserting a python interpreter etc…