Re: 429 Too Many Requests https://validator.w3.org/nu

Greetings Juan,

On 2025-07-14:

> Hello,
>
> I  want to report a 429 Too Many Requests  we are getting on our CI
> Pipeline  since last Friday afternoon (GMT+1) from
> https://validator.w3.org/nu . I'm also getting the same issue today from
> both the CI Server and my local Linux box. I wanted to ask if there has
> been any changes, because up to last  Friday we were having no issues of
> that sort. I also looked for a mirror ofhttps://validator.w3.org/nu but
> couldn't find one. If possible I would like to avoid running our own vnu
> Server. All I want to validate are two html files.
>
> A quick note would be greatly appreciated.
>
> Best regards,
>
> Juan Pablo


I am not aware of changes to W3C infrastructure which would cause that, 
but based on the status code, I do not think this is due to one. 429 Too 
Many Requests does not mean that you personally are requesting too much. 
It can mean that the total rate of requests to the server is excessive. 
So this problem is hopefully intermittent, and noticing it when you did 
not before probably only means that the rate of requests has increased.

Do you still get the problem? The use case which brought me here appears 
to work well as of today, but if you do, this error code was reported 
previously on https://github.com/validator/validator/issues/1715, 
although that ITS is reportedly not intended to track such issues.

I have not experienced issues since last year, but as I noted there, if 
this is regular (which appears to be the case, if it lasted from at 
least April 2024 to July 2025), details and perhaps statistics would be 
warranted. I sent my own hypothesis there about why the validator may 
get unwarranted load, but the very first report, by GitHub user MatinF, 
highlights that he is running about 200 validations daily. I don't know 
if that is a judicious usage of W3C resources, but if there are numerous 
entities who do such automated tests, that may be a more likely primary 
cause, likely to persist. It would then be particularly important to 
have a ticket tracking this to have somewhere to discuss causes and 
solutions and offer workarounds.

Note that I am not subscribed to this list.

-- 
This mail's original content (non-quoted parts) is available under the Creative Commons Attribution-ShareAlike License 4.0.

Philippe Cloutier
https://www.philippecloutier.com