Open licensing for proprietary audio and plug-in standards could enable the entire industry to move forward on some critical work. So it’s great news that Steinberg this month announced not one but two big licensing announcements: first, a dual-licensing model for their ASIO audio driver protocol for Windows (including an OBS collaboration), and now a permissive MIT license for the mighty VST3 plug-in spec.
First, before someone yells at me, yes, absolutely, there are existing open-source standards that work across platforms. That includes the crucial JACK audio system, as well as the CLAP and LV2 plug-in formats. But I’m confident that Steinberg opening up its own standards, far from detracting from those cross-platform and community-driven initiatives, removes a major barrier to developers. (To clarify: this isn’t necessarily news on VST 3; an open license was available previously. It’s just been updated from GPLv3 to a more permissive MIT license. VST is already supported across many open tools, from a Pure Data external to Ardour hosting support.)
For end users, more open tooling means more choice, more integration, and tools that install more easily across hardware and software platforms.
And we need this now. It’s those times when the music tech industry faces headwinds that it’s most important to work together and remove barriers. It’s like letting go of weights on your balloon, basically.
VST 3.8
First, today’s announcement, VST 3.8 SDK. The MIT License means free use, modification, and distribution so long as you retain the original copyright and license text. That’s it, so it’s free for use across commercial and non-commercial, free/open source/libre and proprietary projects. And this is relevant across all platforms: macOS, Windows, and Linux.
They’ve also improved the SDK, enhancing support for both MIDI 2.0 and VSTGUI.
See notes on the licensing below. But the short version is this: MIT licensing means there’s an open path for VST 3 going forward. Unlike VST2, VST 3 can’t be discontinued; its source will always be available under an open license, and now also a license that permits you to incorporate the SDK without releasing your own source.
ASIO, OBS
ASIO is Windows-specific but also significant.
ASIO’s licensing now offers a GPLv3 option alongside the existing proprietary license model. GPLv3, as opposed to MIT, is copyleft — so the projects you make with GPLv3 are also GPLv3. Projects like VCV Rack, incidentally, are GPLv3-licensed, though a handful of projects (Ardour!) use GPLv2.
OBS figures in this, too. By adding the GPLv3 option, Steiberg says they also enable a technical partnership with OBS, the popular live streaming/broadcast/screencasting/screen recording tool. Steinberg will sponsor OBS at the “diamond tier,”| and those of you who wanted this already know why it’s important. “The OBS community has been asking for ASIO support for a long time,” OBS Project’s Product Lead Taylor Giampaolo said in a statement.
And I would assume if ASIO support opens up new possibilities for OBS, other projects may be eyeing it, too. I’ll keep tabs on that.
What a permissive license means for VST
Clarification: I claimed that this might remove some obstacles to developers, but neglected to point out: the VST 3 SDK already had a dual license with a GPLv3 option. Open source developers so far have told me that this doesn’t shift anything significantly for them.
Steinberg’s Director of Engineering, Ralf Kuerschner, responded to CDM with some ways to think about this:
What’s different here is the licensing. The VST3 SDK was previously available under a dual license (proprietary and GPLv3). Now that Steinberg has re-released it under the MIT License, it’s much simpler and more permissive.
This change has several important implications:
1. No more administrative overhead: developers no longer need to sign or manage a proprietary Steinberg VST3 license agreement.
2. No source disclosure requirement: under the previous dual license, using GPLv3 meant that derivative code had to be open-sourced. With MIT, developers can now integrate VST3 freely into closed-source or commercial projects without needing to release their source code.
3. Simplified branding rules: use of Steinberg’s VST logos or trademarks is now optional; the terms only apply if a developer chooses to use those logos.
4. Perceived longevity and clarity: after the discontinuation of VST2 (which was never open source and officially ended in 2018), this step helps reassure developers that VST3 has a stable, future-proof legal footing under a standard open license.
5. Ongoing development and stability: unlike VST2, which has been discontinued, VST3 continues to be actively developed by Steinberg, with several updates released each year. The format also delivers better overall system stability thanks to its modular architecture, separation of processing and UI, and improved resource handling.
Most of that you already understand if you know the difference between GPLv3 and MIT (or copyleft and more permissive licenses, generally). But to summarize, this lightens the load on developers using proprietary licensing.
You’ll notice that what Ralf emphasizes most is VST2 versus VST3. Some readers also pointed out the frustration with VST2 being deprecated — and licensing being terminated. (VST2 support lives on, anyway, and check out projects like yabridge that make everything run on Linux — even 32-bit plug-ins and VST2 that might not be supported by modern Mac and Windows hosts.)
If it seems like I am cheerleading this, I absolutely am — not VST over other formats, but open licensing for the platforms we depend on. I think I overstated the benefits to existing FLOSS projects, though not having to sweat developer agreements and logo terms is welcome. But generally, we benefit from technology having life beyond just a single party and proprietary license, especially among other uncertainties in the world.
“You’re right that from a purely technical perspective this change doesn’t suddenly enable new functionality for open-source hosts or plug-in developers,” Ralf tells us. “Later down the roadmap, it will.
Learn more
For more on the licenses, skip the AI-generated summaries and go straight to the GNU source. If it hasn’t got a hand-drawn picture of wildlife, I don’t trust it! They probably drafted this in emacs:
But if anyone has ideas about how to use this, I know I can count on the CDM reader community for that, so discuss here or chat on Mastodon!
VST 3 Now Available Under MIT License [Steiberg press release]
New ASIO Open-Source License Paves Way for OBS Partnership
Image courtesy Steinberg. See, it’s like they’re pointing at the software that’s open-licensed. Never mind.
Live long and prosper. GNU’s not UNIX.
Updated/corrected, November 4: I clarified claims about the significance of the MIT License for VST 3, and added commentary from Steinberg.