Checking the correctness of a combination of bank identification number (BLZ) and account number is a complicated task in Germany. There are about 140 different methods how this combination is checked depending on the bank from which the combination originates. A library which solves this problem is ktoblzcheck. At the moment you could use it simply as a C++ library or with the python wrapper but there isn’t a simple way to use it in Node.JS. Due to this lack of support I wrote node-ktoblzcheck. Until now it supports the two main functions I needed.

If you know a BLZ you could get the name of the corresponding bank via

ktoblzcheck.getNameForBLZ(37010050)

If you are supplied a combination of a BLZ and an account number, checking if they are valid together is done with one handy call:

ktoblzcheck.checkBLZAccount(50010517, 0648489890)

For a correct combination the above code should return 0.

Using node-ktoblzcheck is as easy as calling

$ npm install ktoblzcheck