Glulx is a story file format for Interactive Fiction (IF) games. It is developed and maintained by Andrew Plotkin. The purpose of Glulx is to eliminate some limitations of the original Z-code format, most notably the file size limit. Glulx files may be stand-alone or they may be included in a Blorb archive.
For a non-Blorb file, the first four bytes are the ASCII characters "Glul". For Glulx files compiled by Inform, the ASCII characters "Info" are found at offset 36.
- .ulx: standard extension for a stand-alone Glulx file (also rarely .glulx)
- .blb, .blorb, .glb, .gblorb: used for Glulx files packaged in the Blorb container format. Usually along with other resources such as images and sounds.
- Glulxa (C source code, open source, IF Archive: a Glulx assembler by Simon Stapleton
- Inform: an IF development system by Graham Nelson
- Superglus: a Spanish IF development system
- Git (cross-platform, open source, website): not to be confused with the source code control software of the same name
- Glulxe (cross-platform, open source, IF Archive)
- sensory.blb: Sensory Jam, by Andrew Plotkin. A short Glulx demonstration.
- DeadCities.gblorb: Dead Cities, by Jon Ingold