Responsibilities
Regularly update our Magento installation
Install security patches
Develop new functionality
Must be a self-starter & be able to work with minimum supervision
Exp. In modules/extensions development/customization.
Exp. In Theme integration/customization.
Exp. In API creation/integration.
Work on Magento integration with external systems, viz
CMS/CRM/ERP/Payment/Shipping etc.
Good understanding of database structure of Magento 1.9 & 2.