Jade Reader is an open-source text file reader for Android users who want to learn Japanese. The program has a built-in offline Japanese-English dictionary that does not require an active internet connection. The dictionary used in the program is the EDICT dictionary from WWWJDIC, which was converted to a format suitable for Android devices. The reader has the ability to detect file encoding and can easily read HTML/TXT files from AozoraProvider.

The program's algorithm for searching words is based on Rikaichan for Firefox. When searching for a word, the definitions are displayed on the same activity as the text, allowing the reader to understand the context of the word. Users can also save words for future review or copy them to the clipboard for further investigation in other applications such as Anki.

Jade Reader has several features, including highlight and bookmark functionality, horizontal/vertical mode, and the ability to automatically de-inflect verbs and adjectives. Additionally, other applications can share text with Jade Reader, making it easy for users to save text. The source code for the program is available on Bitbucket, and users can contact the developer for any problems or to request bug fixes or enhancements.