The term “standard rate” refers to the rate at which VAT is charged on most goods and services on which VAT is chargable, ie. items which are not covered by reduced rate or zero rate exceptions.
As part of the 1992 EU VAT Directive (92/77/EEC) member states were compelled, as of 1st January 1993, to set their standard VAT rate no lower then 15% and limit the items which qualify for reduced rates to those set out in a European Union -wide list (with some exceptions). The initial Directive specified that the 15% lower limit would stand until 31st December 1996 but this rate has not been modified since the directive.
The standard rate is the rate at which digital services will, on the whole, be taxed. If you are trading with European countries other than your own it is always advisable to seek further professional clarification on the rate you should charge for your goods or services.