Can’t reach the online documentation, Service Unavailable (503)

Hi, I can’t reach the online documentation at:
since some days I get only:

Service Unavailable (503)

The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Does anyone else have that?

Yes, I posted a message asking for Steinberg to fix this a few days ago.
It’s almost Christmas so many people are probably on vacation atm.

Same here.

Should be online again…

As of June 8, 2022 I can’t reach the web-site Is it only on my side or anybody else having such issue too?

Please use now this:
VST - VST 3 Developer Portal (

Thanks for letting know, however I need Halion documentation, which was at as well. Has it been moved somewhere also?

not yet for HALion, we try to avoid confluence backend which has from time to time virus… (Critical Atlassian Confluence zero-day actively used in attacks)
As soon as the server is updated (security fixes) the HALion dev doc will be available again…

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Steinberg Developer Resource - Steinberg Developer Home - Steinberg Developer Help is working again…


is the Developer Resource down again? I get a “Non Existent Domain” error from my DNS server for


It seems to work for me…
But for VST3 use: VST - VST 3 Developer Portal (

Not working here.

Well, you’re probably sitting directly left of the DNS server, aren’t you? :wink:

It’s not working here.
I tested querying the providers DNS directly and even the primary name server for the domain. The result is always “Non-existent domain”.

The serial of zone is “2022060301” - is that correct? Seems recent at least.

Querying works:
Server:  UnKnown


Querying does not work:
Server:  UnKnown

*** wurde von UnKnown nicht gefunden: Non-existent domain.

Btw., I’m looking for the HALion docs there.

Not working for me either (Las Vegas)

I don’t know if the “.help” link is supposed to redirect to the documentation, but this one works for me VST - VST 3 Developer Portal (it’s on github so not surprising…)

Yes, I concur - the web-site is not working for several days now. Halion documentation is unavailable.

Yep, I can’t access that domain at all - @Yvan if you can see it, then you’re using a different DNS from the rest of us. Have you checked it at home on a different device, and maybe 4G on your phone?

They moved a bunch of docs out of the VST3 SDK, into this separate site. (I remember being annoyed at the time because it meant I couldn’t read any documentation if my internet flaked out. I didn’t imagine they’d accidentally make the whole thing unavailable!)

I was trying to look up the .vstpreset file format, which should be here. I eventually found the docs I needed by checking out d8e73177 in the docs/ sub-directory (3.7.1), but it’s also on this other site which I saw for the first time when pongasoft linked to it here.

Yeah, I hope some solution is on the way…

In the meantime you can use the archived version here: Steinberg Developer Resource (archived version). It is slow but better than nothing until the site is up and running again or the content moved elsewhere.

@Yvan: Any luck with verifying the DNS issue?


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We had to take down the site for technical reasons. It will return in the near future.

Is the site still having issues?