I've looked thru the API specification, it's a fairly standard market feed.
I wrote distributed sampling and trading APIs for crypto exchanges; I grasp enough Portuguese to understand the spec.
I'd write the backend in C++, with JSON or plaintext configuration files for setting pairs and account credentials. If you intend to store market data into a DB, I can write a connector toward Mysql or Postgres, and I will need details on your data structures if you have them already defined. Alternatively, the program can export to CSV, hourly, daily or continuously. This would be a console program without GUI meant to run as a background process.
I want to provide a configurable deploy-and-forget software which self-manages anomalies / exceptions and is expected to always behave as intended, eg. in case of temporary DB unavailability (manual maintenance) it would temporarily allocate feed data in memory. You didn't discuss about a feedback channel for monitoring the correct functioning of the daemon, eg. connection unavailable, account credentials refused, etc. This could be done as a separate project using existing system monitoring tools, eg. Munin.
Note that I will need access to the API during the development, in order to test and debug locally; it wouldn't be feasible or timely to debug it remotely on your computer.
I will present you with a raw prototype within a few days, and then after feedback I will refine it further.
Obviously I'll need more details on everything