To test the code during development you need to have at least one active account.
You need two accounts to test transactions that involve more than one account (e.g. Transfer Funds). It doesn't matter the account type.
It could be either Business or Personal.
To open up an account you must go to https://www.paxum.com and click on Sign up button, then follow the instructions on the screen.
Use the account credentials to submit all your requests and to be sure you are not generating any live transactions you have to add two more parameters to each request:
Set the value to ON
The error code you wold like to receive back after the input data is validated. E.g. 00, 51, ...