What is the GBK file format?
.gbk is the file extension for InterBase and Firebird database backups produced by the gbak command-line utility. Although .gbk files are bundled with Delphi and RAD Studio (as the sample employee.gbk InterBase database), the format belongs to the InterBase and Firebird database engines.
A .gbk backup is a portable binary dump of a complete database: its domains, tables, indexes, triggers, stored procedures, and all table data serialized by gbak. It is not a live database file and is not human-readable. To use it you must restore it into a live database with gbak -c (create) or gbak -r (replace). Firebird uses the same tool but conventionally names backups FBK.
The reason .gbk appears in Delphi documentation is that the InterBase Local example ships employee.gbk - a backup of the classic employee sample database. Restoring it gives developers a ready-made local database to prototype applications and focus on database access interface design without connecting to a production server. Delphi offers a rich library of prebuilt components and extensive support for database management systems, making it a natural environment for developing with restored .gbk databases.
Security & safety
RISK: LOWA .gbk is passive backup data, not executable, so it can't run by itself. Real cautions: (1) it can contain an entire database of potentially sensitive records - treat it as confidential and store/transfer it securely; (2) restore only onto a trusted server, since a malicious backup could carry triggers/stored procedures that run on the restored database; (3) restore with a compatible-or-newer engine version, or the restore will fail. Keep the .gbk read-only until you have a known-good restored copy.
Format details
in a nutshell- GenBank sequence file (bioinformatics) - A plain-text NCBI GenBank flat file (DNA/RNA/protein with annotation) also uses .gbk (and .gb); open with SnapGene, UGENE or a text editor.
- GBK (Guobiao Kuozhan) Chinese character encoding - GBK also names a Chinese (Simplified) character-encoding standard, not a file format - relevant when text is mojibake.
- PFsense / config and game level backups - A few applications reuse .gbk as a generic 'backup' suffix (config or level backups), unrelated to InterBase.
Programs that open GBK files
Windows4 apps
gbak (InterBase / Firebird command-line)
Free Restore, don't open: run gbak -c -user SYSDBA -password masterkey backup.gbk new.gdb then connect to new.gdb.
IBExpert
Freemium Use Services > Restore Database to restore the .gbk into a live InterBase/Firebird database, then browse it.
Embarcadero InterBase
Paid Use IBConsole's Backup/Restore (or gbak) to restore the .gbk; the sample employee.gbk targets this engine.
Delphi / RAD Studio
Paid Delphi ships the employee.gbk sample; restore it via IBConsole/gbak, then connect from a Delphi data app. 
macOS1 app
Firebird server + gbak
Open-source Install Firebird, then gbak -c backup.gbk new.fdb to restore and access the data. 
Linux1 app
Firebird server + gbak / FlameRobin
Open-source Restore with gbak, then browse/query the restored database in FlameRobin (free admin GUI). Technical details
deep spec| Format type | Transportable binary database backup (gbak logical dump) |
| Developer | Borland / Embarcadero (InterBase); Firebird Project |
| Encoding | Binary (engine-specific backup stream) |
| Byte order | Platform-independent (gbak makes the backup transportable across platforms) |
| Compression | None by default (logical, uncompressed dump; often externally zipped for storage) |
| Encryption | None in the classic format; modern InterBase supports encrypted backups separately |
| Typical size | ~600 KB (employee.gbk sample) to many GB for production databases |
| Associated OS | Windows, Linux, macOS (via InterBase or Firebird server) |
| Content | Domains, tables, indexes, triggers, stored procedures, and all table data (metadata + rows) |
| Restore command | gbak -c source.gbk target.gdb (create) or gbak -r (replace existing database) |
| Version compatibility | Backup ODS version must match a compatible-or-newer engine for successful restore |
| Firebird equivalent | Firebird conventionally uses .fbk for the same role, produced by the same gbak tool |
| MIME type | application/octet-stream (no registered MIME) |
| Integrity | gbak validates record and structure integrity during restore |
| Released | 1990s (InterBase gbak backup format) |
| Latest version | Tied to the InterBase/Firebird engine version that created it |
| Specification | docwiki.embarcadero.com |
GBK conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about GBK files.
Frequently asked questions
What is a GBK file?
How do I open / restore a GBK file?
gbak -c -user SYSDBA -password masterkey backup.gbk new.gdb, or use a GUI like IBExpert/IBConsole (InterBase) or FlameRobin (Firebird). Then connect with your application.
