API interface
Accounting software online mKsiegowa.pl has API available that allows importing sales invoices.
API interface based on XML is documented here: API documentation.
Before using API please configure it in Setup module -> API Setup.
API Setup
API setup screen is shown below:

API security key
The security is used to secure connection to mKsiegowa. The same key that is etup here must be used in every XML file sent to mKsiegowa.
If you don't have the API key generated use the link Generate new API key.
Customer setup
For any new customers that are sent via API the program need to know what is the default configuration. Use one of the entries in Customer database.