The NCBI Multiple Sequence Alignment Viewer (MSAV) is a versatile web application that helps you visualize and interpret MSAs for both nucleotide and amino acid sequences. You can display alignment data from many sources, and the viewer is easily embedded into your own web pages with customizable options. An even simpler way to use MSAV is to use our page, upload your data, and share the link to a fully functional viewer displaying your results.