Prior to 2017, all W3C standards were free for anyone to implement, allowing free/open browser developers to create their own rivals to the big companies' offerings. But now, a key W3C standard requires a proprietary component to be functional, and that component is under Google's control, and the company will not authorize free/open source developers to use that component.

Control any MIDI enabled hardware: syntesizers, drum machines, samplers, effects.

Create custom interfaces.

Host them as VST or AU plugins in your favorite DAWs.

The open source community produces a large amount of software for different uses. I have already told you about open source tools for interactive fictions. Here are eleven open source tools to help authors be creative.

Axiom is an extremely flexible node-based realtime audio synthesizer. It was originally designed for size-constrained environments such as PC intros in the demoscene, but is entirely open source and is becoming an excellent free tool for any musician.

Features:

• Musician-friendly (ie knobs and sliders) interface
• Highly customizable and flexible through a node editor and custom scripting language, named Maxim
• Export to replayer with no dependencies (not even the standard library)
• Use any DAW with VSTi support for note editing and automation

WireMock is a simulator for HTTP-based APIs. Some might consider it a service virtualization tool or a mock server.

It enables you to stay productive when an API you depend on doesn't exist or isn't complete. It supports testing of edge cases and failure modes that the real API won't reliably produce. And because it's fast it can reduce your build time from hours down to minutes.

Vanna is an internal feature flagging service used at PBS. It helps deliver new features to users quickly and safely. This is an example client implementation for browser based Javascript.

More info in this article at Dev.to.

Focused on high-quality sound processing and a highly usable interface Calf studio gear is designed to give you a professional production environment for your open source operating system.

Play your SF2 sample banks, create filthy organs, fatten your sounds with phasers, delays, reverbs and other FX, process your recordings with gates, compressors, deesser and finally master your stuff with multiband dynamics - for free!

The Infection Monkey is an open source Breach and Attack Simulation (BAS) tool that assesses the resiliency of private and public cloud environments to post-breach attacks and lateral movement.

Neat free opensource audio tools for Linux.

KXStudio is a collection of applications and plugins for professional audio production. KXStudio provides Debian and Ubuntu compatible repositories and its own Linux Distribution currently based on Ubuntu 14.04.5 LTS.