CSV conversion & parsing to json

We are needing to export data from one application and import into another. Application A will be exporting two sets of data. 1: Appointments, and 2: Tasks. Both of these will be exported manually as CSV files on a regular basis (daily / weekly/ as required) We need an app to convert them to json files to be read into Application B (Accounting Software). We're not too concerned as to how the software is written, but it needs to run on Mac OS X Lion or later. It will likely run on a server that is already running Postgres and other apache processes. Application B is already built to import json files that it is expecting, so this small script/software needs to parse the csv into the appropriate json format. There is one small complexity, in order to parse correctly, the script/software needs to do a lookup in another json file to convert a name into a number. Please see attached files. Ideally this program will 'watch' a folder and when a file is dumped in it will parse it and log if it's successful or not. The lookup json files will always be at a specific path. This is stage 1 of the script / software. It needs to be open to adding complexity and more functionality in the future. Eg. Potentially exporting customers from software A, and updating Software B's Customer json file.