APK is a archive format: it stores data in the APK format. CPIO is a document format that stores data in the CPIO format. This extracts the document from the archive so it can be opened directly. 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 CPIO natively or when the target platform only accepts CPIO. 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.