We don't support configurable product as of the moment, a limitation in the Magento API.
All products pushed from Vend to Magento as simple products.
However, you can export your Magento products with your configurable products and child products and map them in Vend with product variants, please email firstname.lastname@example.org for further information.
If you are happy to accept that Vend products push to Magento as simple products, you may want to read this article on how to deal with Magento configurable products once pushed:
Posted by Jason Shico