Bridge program/script between MS SQL database and iOS app

We are looking to have a bridge program developed to pass data back and forth between our MS SQL database and a third part iOS app. On one side we have our MS SQL database. On the other we have a third party iOS device which will scan barcodes. The iOS device will be using Direct Scan to URL (DSU). By doing this it will POST scan data directly to the URL and it will be using our LAN as the URL (it will not be going out to the web). We will have several mobile devices scanning at the same time and will need the local database server to instantly validate and report back to each device. This needs to be optimized for high volume simultaneous requests back to the database server. Flow: Barcode is scanned in the iOS device and the iOS software will send the variables via HTTP POST to the database server A program (or other means) on the database server (running Windows 7) will receive the request and check it against the tables (about 6 tables) to see if the scanned number is valid. If it's valid it would update the database. It will then send an xml response back to the iOS app. The project requires a program to catch the HTTP POST data, pass it along and validate on the SQL database, update the database and then return a result back to the iOS app. I can furnish more details on the iOS api and the database flow upon request. I would rather not create a stored procedure within the database for this bridge and have it run as a small program if possible.