Software that ‘emulates’ other software does not breach copyright

The Advocate-General of the European Court of Justice (ECJ) has given his opinion that writing software that emulates the functionality of other software is not a breach of the copyright in that other software.

A business wrote software that emulated the functionality of software written by another business, and meant users of that other software no longer needed to pay ongoing fees to the other business. The other business claimed that its copyright had been breached.

The High Court in the UK provisionally ruled that copyright law protected software source code, but not the functionality of software. It was therefore open to another business to write new software that emulated the functionality of existing software, provided it did not copy or use the same source code. It asked the Advocate-General of the ECJ to define the scope of the legal protection conferred by copyright on computer programs under the relevant EU Directive. The Advocate-General’s opinion is not binding on the ECJ, but is usually followed.

The Advocate-General has agreed with the High Court. He gave a specific example of a program for reserving airline tickets, which will need to help the user find flights, check availability, book seats, give their details, pay, and download their ticket.

He said "it is… legitimate for computer programs to exist which offer the same functionalities. There are, however, many means of achieving the concrete expression of those functionalities and it is those means which will be eligible for copyright protection."


A business writing software should take specialist advice on whether and how it can protect itself against other businesses copying its functionality if breach of copyright claims cannot be brought.