Aims to balance the goal of giving the complete picture of possible coding exons, with the need to stay grounded in terms of the verifiability of the actual function of the sequences it collects. Thus it relies on the ENSEMBL’s annotation of ‘known’ (‘known’ here being the actual annotation term used, hence the quotes) human exons as the anchor for the search and for the results presentation. To these, ExoLocator adds the search for ostensibly missing exons in orthologous protein pairs across species, using an extensive computational pipeline to narrow down the search region for the candidate exons and find a suitable template in the other species, as well as state-of-the-art implementations of pairwise alignment algorithms. The resulting complements of exons are organized in a way currently unique to ExoLocator: multiple sequence alignments, both on the nucleotide and on the peptide levels, clearly indicating the exon boundaries. The alignments can be inspected in the web-embedded viewer, downloaded or used on the spot to produce an estimate of conservation within orthologous sets, or functional divergence across paralogues.