縦書きプレビュー for Jota is an Android app developed by Aquamarine Networks that allows users to view their text in a vertical format while editing in Jota+. This app is perfect for writers and editors who need to check their work in a vertical orientation, such as for novels and other long-form writing projects. The app supports ruby and Japanese line-breaking, making it easy to check the text like a digital book. The cursor position is synchronized between the editor and vertical view, allowing users to switch seamlessly between the two screens. The app includes a manuscript paper mode, scroll with left and right volume keys, and supports font size expansion and contraction. The app includes IPA Mincho, IPA Gothic, BIZ UD Mincho, and BIZ UD Gothic fonts, and supports English text in simplified vertical display. The app is free, but users must purchase a license within Jota+ for usage of more than 2000 characters.