Is it mandatory to employ a professional representative to file a request for unitary effect?

Mandatory representation depends on whether your residence or principal place of business in an EPC contracting state. If it is, you may act on your own behalf in proceedings before the EPO, also with respect to the Unitary Patent. Alternatively, you may decide to employ a professional representative. If you do not reside or have your principal place of business in an EPC contracting state, you must appoint a representative and act through them in all EPO proceedings concerning the Unitary Patent, including the procedural act of requesting unitary effect (see Rule 20(1), (2)(l) and (3) of the Rules relating to Unitary Patent Protection). However, you do not need to act through a representative when paying the fees, irrespective of your residence or principal place of business (Article 6 of the Rules relating to Fees for Unitary Patent Protection).