VST API license wording questions

Hi people,

The context and background

On 2009, I registered in the developer zone to get VST API documentations (but I had to recreate an account to login the forum today, I don’t know why). At that time, I created my own host for personal use on Windows XP. I’m now running Ubuntu since I have no access any‑more to a Windows box. For various reasons, I’m not happy with VST support on Ubuntu (and Linux in general), even with that of Jost, which I initially though was looking promising.

So I investigated about why the support on Linux is so poor and in the while, I though about reusing my own personal VST host/client wrapper and adapt it for Ubuntu, for VST without native UI (only the abstract UI, i.e. specification of VST parameters, no per VST GUI).

Doing so, I learned about a complain about the SDK API terms which I initially though was FUD but which appears to be founded: it has to do with some surprising (surprising to me at least) wordings in the VST documentations.

The questions

What precisely and concretely means these wordings from VST2 and VST3 ?

From VST2: “You cannot: […] re-work or otherwise pass this technology off as your own.”

From VST3: “The Licensee has no permission to […] This includes re-working this specification, or reverse-engineering any products based upon this specification.”

What means “rework” and “reverse engineer” in this context? Does that mean that any VST protocol implementation (as this is mainly a communication protocol) must be implemented with the Steinberg VST SDK and nothing else? Or with other words, does that mean the protocol is kind of patented or something like that?

Basically, I would like to know if I can use my own implementation (which does not include a single line from the Steinberg VST SDK source) for things others than just personal use.

I have other questions, but these questions will vary depending on the answer to this one.

Thanks for any lightnings.

It would probably make more sense to ask this on the VST developer list than here …

My reading of the lines, for what it is worth, is simply that you cannot take their code and IP and present it as your own work or code, that is different from including their code in the final product, BTW the lines have no legal standing when it comes to any code or IP but their own.

The VST3 line does exactly what it says on the tin, the library is intended to help people make VST3 compatible plugins, not to help competitors make competing VST3 hosts. Note that a number of other companies have introduced VST3 compatible hosting systems without any code or licensing from Steinberg so they are not out to stop you using the standard, merely protecting their own IP, they are an IP business after all.

As to why there are no current VST3 implementations on Linux, probably for the same reasons there are no modern Extended Pascal compilers or modern IDE’s on Linux, no one has been willing to do the work so we are stuck with Borland Pascal/Delphi clones that have back ends with similar quality output as 80’s compilers and old IBM behemoths like Eclipse. Open source only works if someone is willing to actually do the code …

I will have to search my mails archive to get it back. However, I also wanted to ask this publicly, so that people wondering the same and searching the web for it, will see the answer.


So if others already did it, and Steinberg did not sue them, that should be OK. So it’s OK if one does not claim it to be VST (and I guess, does not use the VST logo to advertise) and just say it’s VST compatible.

Yes, I’m aware of all the issues coming with “free as in beer”. After what you said (and there was no objection from anyone), it seems the things I could read on Linux dedicated sites, was mostly wrong and it’s just about Intellectual Property not about preventing interoperability (which is not disallowed)… If I understand you correctly, VST can really be seen as a standard, as long as IP is not violated.

I will re‑ask it on the developer mailing list when things will become more serious.

Thanks for your reply.