Currently there are two web service calls that will allow you to accomplish this easily. The first one is used if you do not have an individual id (ind_GUID) value. In that case the individual matching will be done based on first name + last name + email address. If no individual record is found we will try to match it on first name + last name + beginning of the street line. If no match is found even after that a new record will be inserted. The web service call can be found at:
The second web service call should be used if you already have the individual id of the record that you would like to create a contribution for:
Note: receipts/contributions will be created with default receipt type/subtype information and for the default account and election period.
If you would like just to add a receipt record without updating/adding any individual information refer to:
and the two methods called AddIndividualReceipt that accept slightly different parameters.