ABD File

What are ABD files and how to open them

Are you having problems opening an ABD file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your ABD files.

What is an ABD file?

ABD files have multiple uses, and ArtBase Design is one of them. Read more about the other uses further down the page.

ArtBase Design

ArtBase Design files with the .ABD extension are layout-configurations used by the ArtBase application on AmigaOS and compatible systems. These files store visual design templates ("designs" or "masks") that define how database entries are presented, including field placement, fonts, backgrounds, and styles. The program that creates these files is ArtBase (donationware), which allows users to import CSV-formatted databases and apply custom visual schemes so their tabular data appears as richly styled tables, slideshows, backgrounds, and interactive elements.

Each .ABD file defines one design's configuration: where fields like name, email, rating, or date appear within the layout; how text and images are handled; what fonts, colors, backgrounds, and other graphical features are applied. ArtBase reads these .ABD files when switching designs or masks, rendering data according to the stored visual schema. These files are not the database content themselves but templates for styling that content.

Technically, .ABD files begin with the ASCII text "backdrop= " at offset 0 and often contain internal identifiers like BACKDROP, FORMAT field labels such as NAME, MAIL, DATE, AUDIO, LIST, and layout markers like VBAR, HBAR, HBOUND, VBOUND, PSLIDE among others. These keywords help distinguish the design elements and their settings inside the file.

How to open ABD files

Important: Different programs may use files with the ABD file extension for different purposes, so unless you are sure which format your ABD file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested eight different ABD openers which you will find listed below.

Last updated: August 16, 2026

All known file formats using extension .ABD

While ArtBase Design is a popular type of ABD-file, we know of 2 different uses of the .ABD file extension. Different software may use files with the same extension for different types of data.

The Bat! Address Book

The Bat! Address Book files are proprietary address book files used by The Bat!, an email client by Ritlabs. These files store address book entries such as each contact's name, email address, organization, possibly birthday or other personal fields. They are created whenever a user adds or edits an address book within The Bat!. The contents are saved locally in the user's Mail directory where the program's address books are stored.

These .ABD files are read and written only by The Bat!. When the program starts or when an address book is opened, it loads data from the corresponding .ABD file. When entries are changed, deleted, or added, The Bat! updates the .ABD file. It offers exporting of contacts to formats like LDIF, vCard, CSV, and other text-based formats.

Files of this format begin with a binary signature: the first eight bytes at offset 0 are 0x9189981944000000. Further signatures include a zero sequence at offsets 9 and 13, and the sequence 0x00000000010000 at offset 17. These bytes serve as a magic header for file-type identification.

The filename of each .ABD file typically matches the address book's name in the program, such as TheBat.ABD for the principal personal address book. In addition to regular contact books, special .ABD files exist for security certificates ("RootCA.ABD", "IntermCA.ABD") that become relevant when certificate management in the address book is enabled. The files are located in The Bat!'s MAIL directory.

Various apps that use files with this extension

These apps are known to open certain types of ABD files. Remember, different programs may use ABD files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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