JUCE is an open-source cross-platform C++ application framework for desktop and mobile applications, including VST, VST3, AU, AUv3, RTAS and AAX audio plug-ins.

Synthesizer plug-in (previously released as Vember Audio Surge)

Enhanced version of Cockos' iPlug - A simple-to-use C++ framework for developing cross platform audio plugins and targeting multiple plugin APIs with the same code. VST / VST3 / Audiounit / RTAS / AAX (Native) formats supported. NOTE: THIS IS OBSOLETE, PLEASE SEE IPLUG2:

VST 3 Plug-In SDK

A curated list of my favourite music DSP and audio programming resources

C++ Audio Plug-in Framework for desktop, mobile and web [PRE-RELEASE]

An audio plugin with Pure Data embedded that allows to load and to control patches

A user interface toolkit mainly for audio plug-ins

DSP servers using general purpose networks and computers - https://audiogridder.com

Make audio plug-ins with D

native node addon that allows for instantiation of natively installed VST3 audio plugins

SFZ parser and synth c++ library, providing AU / LV2 / VST3 plugins and JACK standalone client

Various resources related to developing plugins for audio production.

Graph-based audio api for Node.js based on LabSound and JUCE

Collection of JUCE synthesisers utilising the Maximilian library.

A lightweight VST2/3 framework

A basic and experimental guitar modeling amp

VST delay plugin where the repeats degrade in resolution

A VST reverb effect in which the reflections can be frozen, filtered, pitch shifted and ultimately disintegrated.

VST plugin version of the WebSID Commodore 64 synthesizer

Collection of tutorials & resources for the C++ library JUCE

A VST / VST3 / AU / LV2 Reverb Plugin

VST3 version of system-supplied Mac OS X AUNetSend audio plugin.

Audio plugin that lets you use MIDI to pitch-shift via delay to turn unpitched audio into melodies

EP-MK1 is a real-time physical model plugin of an Electric Piano built with Pure Data and Camomile.

Vst3HostDemo

Example of a self contained VST3/VST2 plugin that is not part of the SDK

Free EQ audio plugin (VST3, AU) with modulation

AU / VST / VST3 FM synthesizer which emulates the Yamaha OPL sound chip used in PC sound cards from the 90s.

strum the sound spectrum to create strange sounds (VST, VST3, AU, and App)