Bookstacks is a simple iOS app for managing your book collection. Scan any ISBN barcode to register a book — title, author, and cover image are fetched automatically via the OpenBD API. No account needed; everything stays on your device. Key features: • ISBN barcode scanner + manual entry • Auto-fetch book metadata and cover images • Organize books with custom labels • Set covers from camera or photo library • Search your entire shelf instantly • Available in English and Japanese