API tool to upload daily marketplace inventory

One of our clients is a seller in an online retail marketplace in France called [login to view URL] Currently they upload their inventory every day manually via the “seller interface” using a Microsoft excel template (see sample attached). The problem is that this method has proven to be very unreliable given the size of the inventory files. Even when selecting "purge"methood to replace the existing inventory with the new inventory, the system fails to delete most of the inventory. This results in many products which are out of stock to continue to be sold. Another issue is that It requires him to break down the files to 4 or 5 parts. We want to switch to API to update the inventory. We want to have our own web-based API tool to process our daily inventory uploads for us. Every day we want to manually upload one excel inventory file to the API tool. Attached is the API documentation for this marketplace, the documentation is in French. The operation to update inventory is called SubmitOfferPackage IMPORTANT: in order to replace the old inventory with the new inventory, you need to have this: Attribute OfferPackage/@PurgeAndReplace I want you to host the tool. So you will need to create a webpage that is hosted by you, where I can log in daily and upload a single 15 to 20 MB excel file with the inventory data, and the API tool will feed that data via API to the marketplace, and it should REPLACE all previous inventory with the new inventory. I will need to have a downloadable results where I can confirm the following steps: (1) Old inventory has been fully purged (2) New inventory has been fully accepted by the marketplace (3) Error codes for any products that have been rejected Instead of making a one-time payment for this job, I am want to pay a monthly fee. Because I want this job to be not only creating the tool, but to make sure it continues to work properly. I am sure it will require additional debugging and functionality corrections in the 2nd or 3rd month because the API structure for this marketplace changes constantly and I will need the revisions to be made promptly to keep the tool working flawlessly. This is a long-term reliable relationship that I am looking for with the possibility of more API jobs later. So if you are not generally available to respond, to debug and to address problems that may come up, please do not bid on this project. I am going to set the budget at $240 for 12 months = $20 per month for 12 months. IMPORTANT: When you bid on this project, please place a total bid for 12 months, but remember that this amount will not be paid in one payment. It will be divided into 12 milestones paid monthly. The first milestone payment will be released when the tool has been tested and is working properly. Thanks and good luck.