SnapGene Viewer is described as 'Is revolutionary software that allows molecular biologists to create, browse, and share richly annotated DNA sequence files up to 1 Gb in length' and is an app. There are more than 25 alternatives to SnapGene Viewer for a variety of platforms, including Windows, Mac, Linux, Web-based and SaaS apps. The best SnapGene Viewer alternative is Benchling. It's not free, so if you're looking for a free alternative, you could try Benchling or BioEdit. Other great apps like SnapGene Viewer are UGENE, Genophore, ApE - A plasmid Editor and DNADynamo.