Harmonisation requires comprehensive examination of current practice to understand the aims and approaches of prior work, and a synthesis of the successes and failures in past implementations for the purposes of elaborating a framework to guide future research. Therefore it is our aim to summarise the state of the art for bioinformatic processing of metazoan wocDNA COI metabarcoding, and in doing so assess the potential for  harmonisation. To this end, we performed a systematic review of peer-reviewed studies, collating information on the different bioinformatic pipelines, tasks and tools used in wocDNA COI metabarcoding in >100 recent studies (2011-2020). We use this data to (i) describe the diversity, heterogeneity and reproducibility  of the bioinformatic procedures followed, (ii) identify the extent to which these procedures are compatible with the evolutionary properties of the COI marker, and (iii) identify the key bioinformatic tasks, provide a framework for successful metabarcoding bioinformatics and make recommendations towards harmonised bioinformatic procedures for metazoan wocDNA COI metabarcoding.