Linux Audio Developer's Simple Plugin API
LADSPA is a standard that allows software audio processors and effects to be plugged into a wide range of audio synthesis and recording packages. For instance, it allows a developer to write a reverb program and bundle it into a LADSPA "plugin library." Ordinary users can then use this reverb within any LADSPA-friendly audio application. Most major audio applications on Linux support LADSPA.
Homepage: https://www.ladspa.org/