Extract text from Flashcard decks (FDK)
To convert FDK Decks to another format, you need Flashcards Deluxe or other Data software.
To convert other file formats to the "App Data & Backup" file type, you need software like Flashcards Deluxe or a similar tool.
The .FDK file extension usually represents a digital flashcard deck created for the Flashcards Deluxe mobile application. Less commonly, it acts as a database backup file for the Firebird open-source relational database system.
Users primarily interact with the flashcard variant on iOS and Android devices, using it to store custom study materials, including text, images, and audio. The backup variant is processed by database administrators using Firebird's gbak utility to safely store or migrate database records.
The main disadvantage of the Flashcards Deluxe .FDK format is its proprietary lock-in. You cannot natively import this file into alternative study platforms like Anki or Quizlet without manual extraction and restructuring. For the Firebird variant, the backup file is completely unreadable until fully restored to a live database server; it is essentially a binary dump of metadata and tables, offering no direct access to the data.
For flashcard decks, the best conversion path is extracting the file as a standard ZIP archive to recover the underlying TXT or CSV files and associated media (like JPG or MP3). For database backups, the file must be restored to an FDB database, which can then be exported to standard SQL or CSV formats for wider compatibility.
Because an .FDK file can be either a compressed ZIP archive or a complex binary database blob, standard online converters often fail to process it correctly. Drag and drop your file into convert.guru to quickly identify what kind of .FDK you have. If our analysis detects the supported ZIP-based flashcard structure, viewing internal text and extracting embedded formats will be possible without needing the original app.
Convert.Guru analyzes your FDK file, detects the exact format, and lets you read the text inside.
Users also converted APKG, ANKI and CARDS files.
If you want to convert FDK file to , you can use Flashcards Deluxe or similar software from the "Flashcard Decks & Database Backups" category. In the File menu, look for Save As… or Export….
To convert files to FDK, try Flashcards Deluxe or another comparable tool in the "Flashcard Decks & Database Backups" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our FDK converter.