Start with your first document.

Open or import a document

On Mac, use Open, the File menu, Finder, or drag files into the library. The app references your original files and keeps them read-only.

On iPhone and iPad, choose Import from Files in the add menu. The app keeps its own copy. Identical content is merged; files with the same name but different content stay separate.

Supported formats

Supported formats include verified CAJ with embedded PDF, KDH 2.00, a limited subset of compressed HN, and standard PDF. The .caj extension can cover different internal formats, so not every CAJ file is readable.

Other HN variants, C8, TEB, and some incomplete or unusual document structures are not supported. Keep your original file and try obtaining a PDF from the source.

The input limit is 1 GiB per file. Document complexity and device resources also affect whether a file can be read. Scans without available text cannot be searched or copied directly; OCR is not included.

Some documents can be recovered for reading, but appearance and text order may differ from the original. PDFs exported from the supported HN subset may copy in a different order in other readers.

Read, search and navigate

Use chapters or thumbnails to find a page and adjust zoom and layout. Search and copy depend on the text available in the document.

Mac supports native document tabs, single-page, two-page and continuous layouts. Tabs are hidden when only one document is open. Mobile devices read one document at a time.

Library and reading progress

Successfully opened or imported documents stay in your library. Search by filename and sort by last read, name or progress. Reopening restores your place on the current device.

Removing an item on Mac clears its records and related cache, not the original file. Follow the app prompt to relocate a moved file or renew permission.

Deleting on mobile requires confirmation and removes the app-owned copy, records and cache. An external original imported from Files is unaffected. Documents and progress do not sync across devices.

Transfer from a computer over Wi-Fi

Connect your computer and iPhone or iPad to the same trusted Wi-Fi network, then open Wi-Fi Transfer in the app.

• Enter the local address shown by the app in your computer browser, followed by the six-digit code.
• Upload CAJ, KDH or PDF files, up to 1 GiB per file.
• Keep the transfer screen in the foreground. Leaving it or backgrounding the app stops the service and cancels uncommitted transfers.
• Upload success means the copy and library record were saved. It does not guarantee readability. Covers are prepared in the background; opening a document shows its parsing result.

Export PDF and page images

On Mac, export a PDF from the toolbar or File menu using ⇧⌘E. Image export supports the current page, all pages or a page selection, at 72, 144 or 300 dpi. Available image formats depend on system encoders.

On iPhone and iPad, use export and the system share sheet to save or send PDFs or images to your chosen destination.

Export does not expand format support, add OCR or correct source text. Check the output and keep the original document.

A document will not open?

Check that the file is complete, its format is supported, and the device has enough storage. On Mac, renew file access when prompted. On mobile, retry or import the document again.

If the issue remains, contact support with your device, system, app version, file format and steps to reproduce. There is no need to send the full paper by default.