Synchronize inventory with BigCommerce

Need coders experienced with BigCommerce integration. I need a script / Program to update the inventory automatically in Big Commerce website. You have to read inventory data from an XML file (url will be provided) and match the products in XML file and update inventory in BigCommerce website. There will be 2 separate kinds of XML files and both will need to be processed to update inventory in BigCommerce website. Since the number of products are large, the total products will be divided into batches of approx 1000 products per file. You will need to create a script/program that can be run as a schedule task or cron job. The inventory file XML format will be shared with the winning coder. You will need to tell us what information you need about our BigCommerce website. Experience in working with BigCommerce integration is a must.