COPECO is a joint project between Geneva University and Liège University, with three mainobjectives: 1) to collect post-edits produced by students and teacher corrections, 2) to build an open-source student post-editing corpus and 3) to help systematise the task of translation error annotation (O'Brien, 2011). It provides translation teachers with an online post-editing platform, designed to help them to annotate student post-editing tasks using a shared or personalised annotation scheme.