Your ePub Is fine

Original Article ↗ Hacker News Discussion ↗

EPUB, CSS, and Standards Compliance

  • EPUB is essentially zipped HTML/CSS; in theory easy to render and edit, in practice implementations are inconsistent.
  • CSS is designed to be forward compatible: unknown/illegal declarations should be ignored, not cause failures. Several comments state ADE/RMSDK violate even CSS1 rules by treating minor CSS issues as fatal.
  • EPUB 3+ tied itself to “living” browser specs (WHATWG HTML, modern CSS), which move faster than embedded e-readers. This made some older EPUBs technically non‑conforming, so many tools still target EPUB 2 or 3.1.
  • Debate: some argue the spec is over-ambitious for slow-moving devices; others insist implementations should simply follow the spec and ignore unknown CSS.

Kobo, RMSDK, and Kepub

  • Kobo’s Adobe-based RMSDK engine is widely described as outdated and brittle, rejecting otherwise valid EPUBs.
  • Workaround: convert EPUBs to Kobo’s kepub format (e.g., via Calibre plugins or kepubify). This uses a different renderer with better layout, features (e.g., cross-page highlighting), and fewer compatibility issues.
  • Multiple users install KOReader or Plato as alternative renderers; these often handle EPUBs and PDFs better and ignore problematic CSS.
  • Kobo is reportedly rewriting its software (especially in the EU, tied to accessibility rules) and may be moving away from Adobe DRM, but details and trade-offs are unclear.

EPUB vs PDF and Minimalism

  • Some prefer PDF despite its notoriously complex internals because reader behavior is more predictable and legacy-compatible.
  • Others prefer EPUB but advocate using extremely simple HTML/CSS (or even plain text) to maximize compatibility across old and buggy readers.
  • Several readers strip “fancy” styling, embedded fonts, and modern CSS, arguing ebooks rarely need complex layout.

DRM, Ecosystems, and Device Openness

  • ADE-style DRM is seen as fragile and exclusionary: hard to support as a third-party, and a barrier to new reader software.
  • People describe stripping DRM (when possible) to get standard EPUBs; some library users say ADE no longer works on their systems.
  • Comparisons: Kindle praised for reliability but criticized for lock-in and dependence on Amazon services; Kobo, PocketBook, Boox, PineNote, and other Linux/Android-based devices are discussed as more hackable/open, but with stability, UX, or cost trade-offs.

Adobe, Flash, and Broader Sentiment

  • Strong anti-Adobe sentiment: products viewed as DRM-first and poorly maintained (RMSDK, Flash, sometimes PDF tools).
  • Long tangent compares Flash’s creative power and ease of publishing versus its security, performance, and proprietary problems; used as an analogy for Adobe’s handling of EPUB tech.