Alternatives to Loopback
Create virtual audio devices that combine application and hardware audio on a Mac. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Loopback
Create virtual audio devices that combine application and hardware audio on a Mac.
Replacements
Listings that take over the same core job as Loopback.
BlackHole
Pass audio between Mac applications through a virtual loopback driver.
BlackHole is free and open source under GPL-3.0, providing virtual loopback channels on macOS, but routing is configured in each app or Audio MIDI Setup instead of a visual interface.
VB-CABLE
Route audio between applications through a virtual audio cable.
VB-CABLE is a free virtual audio cable for macOS and Windows that passes one application's output to another, without Loopback's visual routing of multiple sources.
JACK Audio Connection Kit
Connect audio and MIDI applications through an audio server.
JACK Audio Connection Kit is a free, open-source audio server for Linux, macOS and Windows that routes audio and MIDI, but needs compatible applications and careful setup.
Also worth comparing
These listings name Loopback as their own alternative, so the relationship runs both ways.
Audio Hijack
Capture and process audio from Mac applications and input devices.
Loopback is also a paid macOS app but creates virtual audio devices combining application and hardware audio, routing sources rather than recording them itself.
Voicemeeter Banana
Windows virtual mixer with five inputs and five outputs for routing audio.
Loopback is a paid macOS app with a visual interface for combining application and hardware audio into virtual devices, replacing Banana on a Mac.
Voicemeeter Potato
Top-tier virtual audio mixer with eight inputs, eight outputs and insert effects.
Loopback is a paid macOS app that builds virtual devices from application and hardware audio through a visual routing interface, with no Windows version.
Similar software
Related functionality, not a direct replacement.
SoundSwitch
Switch Windows playback and recording devices with hotkeys.