Open-source e-ink reader firmware · Browser tools for content conversion
Everything runs in your browser with one-click transfer to your device
PDF, DOCX, CBZ, CBR, FB2, RTF, Markdown, HTML, EPUB, images. Auto-detects format, classifies PDFs, preserves inline images, handles manga. Existing EPUBs get full optimization — image resizing, grayscale, CSS cleanup, encoding fixes.
Paste any URL, extract article text with Readability parsing, strip ads, preserve images. Queue multiple URLs or combine into chapters.
Photos and artwork to 1-bit dithered BMPs. Floyd-Steinberg, Bayer, Atkinson at native 480×800.
TTF & OTF to .bin format. Live e-ink preview, adjustable boldness and spacing, character set selection.
Build a newspaper from live RSS feeds. Full article text and images via Readability extraction. 15 preset feeds or custom URLs. Cover art and TOC.
Visual editor, 11 premade decks, AI assistant. Import from AnkiWeb or Quizlet. SM-2 spaced repetition output.
Build games and apps with Lua. AI-assisted prompt builder, live e-ink preview, full API reference. Scripts run directly from the SD card.
Custom home screen backgrounds. AI prompts for any style, drag-and-drop converter, 10 themes included.
SUMI is open-source e-ink firmware for the Xteink X4 (ESP32-C3, 380KB RAM). It includes an EPUB reader with real inline images and tables, games, notes, flashcards, and maps. This site provides browser-based tools that prepare content for the device's constraints.