baseUrl parameter in AppModule should be replaced with a working Backend endpoint url for this project. For example: http://192.168.0.1:8080/ (with trailing slash)
Repeated update requests with the same Transaction-Id are accepted (even with altered account_id and amount values) but have no effect on the account balance.
There are no requirements on minimum and maximum balance.
Both successful and failed update requests are saved in the local database. Failed requests can be retried manually in any order and local database is updated accordingly based on the result of the request.