You can usually use plain old JSON anywhere where YAML would be used (e.g. host vars, group vars, vars file includes, I think even playbooks). And internally, m

You can usually use plain old JSON anywhere where YAML would be used (e.g. host vars, group vars, vars file includes, I think even playbooks). And internally, most everything in Ansible is JSON anyways. YAML is for convenience for hand-editing configuration/task files; if you're doing anything that doesn't require hand editing/readability, use JSON.