Open-source e-ink firmware for SUMI & Folio · Browser tools for content conversion
Everything runs in your browser with one-click transfer to your device
PDF, DOCX, CBZ, 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.
Clean up and optimize StarDict dictionaries for SUMI. Pre-builds the offset cache so first lookup is instant. Strips macOS resource forks. Drop .ifo/.idx/.dict or a .zip.
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, 100+ 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.
Connect to your device over Bluetooth and exchange live events. Build BLE-enabled plugins with any AI, run them here — doorbells, text-pushers, whatever.
Custom home screen backgrounds. AI prompts for any style, drag-and-drop converter, e-ink dithering preview.
Send any file directly to your SUMI over Bluetooth. Pick the destination folder, drop files, transfer. Warns about formats that need conversion.
Flash firmware via Chrome WebSerial. One click, no drivers. Supports dual-boot.
Pre-cache your library into the device-native binary format for instant-on reading. Run once, copy to SD card.
SUMI is open-source e-ink firmware for the Xteink X4 and X3 (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.
Folio is a sister firmware focused on the four headline reading apps — reader, dictionary, writer, and chess. Every tool on this site works with both firmwares: custom main pages, Lua plugins, and device formats are shared. They just aren't headline features on Folio.