Software development services provided outside India is export of service.The export of goods or services is considered as a zero-rated supply. GST will not be levied on export of any kind of goods or services. So you may show CGST & SGST @ NIL rate. (As it is not an exempted supply)A duty drawback was provided under the previous laws for the tax paid on inputs(purchase) for the export of ZERO Rated/Exempted goods. Claiming the duty drawback was a cumbersome process.Under GST, the duty drawback would only be available for the customs duty paid on imported inputs intended to be exported.Assuming that the your service was fully generated in India, you would not have paid any Input Tax Credit, so it is irrelevant to talk about claiming the tax paid on input.Hope it helps!#Althz