The Elisp module ob-yaml.el adds support for YAML source code blocks in Org Babel. It was created via trivial modifications of the template file.
The primary aim was to allow for writing and maintaining bigger YAML files (or sets of such files) in a literate programming style by using the powerful Babel subsystem of Org mode. One particular example are Home Assistant configuration files.
Only a subset of Org Babel functionality is required for such purposes, namely editing blocks in yaml-mode, tangling (including noweb references) and possibly exporting. Specifically, YAML blocks needn't be evaluated, and so evaluation-related functions are left unimplemented.