The stls from CadQuery and OpenSCAD are not compressed and so we're throwing away bandwidth and taking a performance hit by not gziping. Gzip for s3 basically needs to be gziped before upload and than have 'content-type' : 'text/stl' 'content-encoding' : 'gzip' set. https://stackoverflow.com/questions/8080824/how-to-serve-gzipped-assets-from-amazon-s3 The obvious part that needs to change is putObject in app/api/src/docker/common/utils.js but there might be a few more nuances. resolves #391