VHD is a document format: it stores data in the VHD format. APK is a archive format that stores data in the APK format. This packages the document into a compressed archive for smaller transfer size. Metadata such as creation date and embedded colour profiles is preserved where the target format supports it. Converting between these two formats is common when the source application does not support APK natively or when the target platform only accepts APK. 1converter processes this conversion server-side using open-source tools. Files are transferred over HTTPS, converted on secure cloud servers, and automatically deleted after 24 hours.