We needed the complete Ansible module documentation in JSON format, so we wrote some code to parse all of the documentation fields from the Python modules, and served it up as a public API.
This data completely free and public - feel free to use it for your projects! We regenerate it when a new Ansible version is released (currently generated from 2.8.1).
Check out the HTML category index here: https://api.playbook.cloud/v1/modules/categories/index.html
Complete API documentation available here: https://docs.playbook.cloud/#/user_guide/using_the_api?id=module-api-usage
Enjoy!