dune-typetree is a module of the DUNE Numerics framework for solving partial differential equations (PDEs) with grid-based methods. dune-typetree is a template library for constructing and operating on statically typed trees of objects. It is based around the idea of defining loosely coupled, componentized algorithms. Component lookup happens through tag dispatch, making it very easy to extend and / or modify existing algorithms as well as constructing new algorithms for existing types of tree nodes.