Sir,
The supply is within taxable territory (India). Therefore you have to pay CGST + SGST or IGST (if supply is inter- state).. The fact that you are invoicing the customer who is located ovewrseas and remittance is made in convertible foreign currency will not make yoiur supply as export.. According to Section 2 (5) of IGST Act, 2017 “export of goods” with its grammatical variations and cognate expressions, means taking goods out of India to a place outside India; According to Section 2 (6) of IGST Act, 2017 “export of services” means the supply of any service when,––
(i) the supplier of service is located in India;
(ii) the recipient of service is located outside India;
(iii) the place of supply of service is outside India;
(iv) the payment for such service has been received by the supplier of service in convertible foreign exchange; and
(v) the supplier of service and the recipient of service are not merely establishments of a distinct person in accordance with Explanation 1 in section 8;