Magento 2 module for loading store layout / blocks in an external file or program.
This blog article & associated module are meant to help you access a specific container or block in your Magento 2 theme from an external system. For example, you may be integrating your Magento 2 installation with WordPress, Drupal, Expression Engine, or another CMS in which you want to load part of the page from your Magento 2 store. Or, you may just want to render a specific element’s HTML outside the context of a Magento 2 controller action.
GPL 3.0
See the official documentation and usage example here: https://www.cadence-labs.com/2017/04/magento-2-load-block-layout-external-file/