Practical answers for getting the most out of your library.
Codex reads documents from the Files app. You can import a book in three ways: open it directly from Files, Mail, or Safari and choose Open in Codex; drag a file into the Codex library on iPad or Mac; or place files in your Codex folder in iCloud Drive and they'll appear automatically across your devices.
Codex reads EPUB 3 and PDF files of any size. Both formats are treated as first-class — the same navigation, search, annotation, and lexicon tools are available across both.
Codex requires iOS 17 or later, iPadOS 17 or later, or macOS 14 (Sonoma) or later.
Yes. The first time Codex opens a very large document — anything over a few hundred megabytes or several thousand pages — it builds a search index in the background. This happens once per document. Every subsequent opening is fast. You can keep reading while indexing completes.
Codex relies on the document's embedded TOC. Some PDFs — particularly older scanned books — don't include one. You can still navigate using full-text search, bookmarks, and page jumps. EPUBs almost always include a structured TOC and will display nested chapters automatically.
Tap the TOC button in the toolbar to open the navigator. Tap any chevron to expand or collapse a section. Codex remembers which sections you had open, so the structure stays the way you set it up.
Touch and hold any word in the text and the lexicon popover will appear with the entry from your active reference module. Tap any link inside the popover to drill deeper, or tap outside the popover to dismiss it.
Where a document includes inline references, Codex turns them into tappable links. Tap a reference to see the target passage in a popover, or tap the arrow icon inside the popover to jump to it directly. Your reading position is preserved — swipe back to return.
Annotations are stored locally on your device, with optional iCloud sync between your Apple devices. They are not written into the original file, so the source document remains untouched. You can export annotations from Settings → Annotations → Export.
Codex syncs your library, bookmarks, reading position, and annotations through iCloud, using your Apple ID. Make sure iCloud Drive is enabled in Settings → [your name] → iCloud on each device, and that Codex is switched on in the iCloud apps list.
First, confirm you're signed into the same Apple ID on each device. Then check that iCloud Drive is enabled and that Codex is permitted to use it. If the issue persists, try opening Codex on each device with a stable Wi-Fi connection — initial sync can take a few minutes for large libraries.
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support@graphe.one