EPUB is a ebook format: it packages HTML, CSS, and images in a zipped OPS container as an ISO-standardised ebook format that reflows text to fit any screen width. PPM is a document format that stores data in the PPM format. This converts the reflowable ebook layout into a fixed-page document format. 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 PPM natively or when the target platform only accepts PPM. 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.