AlignmentViewerAlignmentViewer is multiple sequence alignment viewer for protein families with flexible visualization, analysis tools and links to protein family databases. It can handle protein families with tens of thousand of sequences and is particularly suitable for evolutionary coupling analysis, preparing the computation of protein 3D structures and detection of functionally constrained interactions.http://alignmentviewer.orgalignmentviewerbiotools:alignmentviewerhttp://edamontology.org/topic_0623Gene and protein familieshttp://edamontology.org/topic_0080Sequence analysishttp://edamontology.org/topic_3168Sequencinghttp://edamontology.org/topic_0160Sequence sites, features and motifshttp://edamontology.org/topic_0084PhylogenyJavaScriptMIThttp://edamontology.org/operation_0492Multiple sequence alignmenthttp://edamontology.org/operation_0564Sequence visualisationhttp://edamontology.org/operation_2479Protein sequence analysishttps://github.com/sanderlab/alignmentviewerRepository10.12688/F1000RESEARCH.22242.233123346PMC7570326Chris Sandersander.research@gmail.comhttps://orcid.org/0000-0001-6059-6270PersonNicholas Paul Gauthiernicholasp_gauthier@dfci.harvard.eduPerson