The ?at= parameter on api.mojang.com/users/profiles/minecraft/<username>?at= suddenly stopped working today

I noticed this yesterday too and would like to flick in and point out how this impacted myself.

I'm currently in the process of developing a Minecraft name lookup website sort of like NameMC, and similarly to them I want all accounts that have ever had a name to show up when you search for it, as this can be very interesting information if you for example find out that a friend of yours used to have a name that you were looking for.
NameMC's approach of this (I think) is just checking if any of the name histories in their own database contains the searched name, and as I assume they have close to every actual Minecraft account (name, uuid, namehistory, etc) in their own database too that seems to work out great for them.
Considering I personally haven't even launched my website yet I obviously don't have a database anywhere close to the size of theirs (I don't even have one at all yet), so as I realized NameMC's approach would not be possible for me I started looking for other ways of getting the same result.

What I came up with was to start off by grabbing the time the first account that had the name changed away from it by appending ?at=0 to the Name>UUID endpoint in order to grab the UUID of the account, and then passing that to the Name History endpoint where the timestamp was available for me. Once I had the timestamp I simply started adding 30 days (155520000) to it over and over again until the Name>UUID endpoint with the new timestamp found a valid account, where it would restart the process but appending ?at=(new name change timestamp + 155520000) instead of ?at=0 until the account it found was the current account with the name.

This way I was at least able to achieve the same result (though I must agree it was quite slow considering the amount of requests I had to make, but this could of course be improved with the use of proxies and better multi threading on my side), but now that you've removed the functionality of the ?at query string this is no longer possible, and to be honest I don't see any other way of me realistically doing this, which I think is very unfortunate as this was a feature I think many of my upcoming site visitors would like.

Jake (or should I say Legendarisk? That's what popped up in my email notification...), I didn't say that the creation date was the only thing this endpoint was good for. My mention of Jomo's program was simply because I know that program is incredibly useful for servers in order to find cheaters on new alternate accounts. This program has existed for years without any issues and this API change essentially kills it, which I don't think is intentional (as Mojang could've killed this program many years ago if they so chose).

Adam, I fully agree with you. This is a very smart way of going about the issue you've been given, and I'm also collecting data on numerous Minecraft accounts (currently have about 12 million UUIDs saved) - this method would be great to get more UUIDs and collect more data... shame that this has been removed now.

I hope Mojang can understand the many use cases of this endpoint and will add it back.

I know it has other uses and they should be fixed, but I was just saying that the creation date part of it shouldn't be fixed.

I am also impacted by this. I accidentally filed a duplicate ticket, but it has a concrete example with curl that might be helpful: WEB-3502. It looks like Mojang's API is ignoring the "at" parameter entirely.

I agree that the profile name history endpoint is not sufficient, as there are use cases in which the player UUID is not known.

In my case, I am writing a plugin that will migrate incomplete data generated by popular ban plugins (e.g. AdvancedBan) to other plugins. Some legacy plugins store only the username of the moderator that issued a punishment, whereas others include (and require) the UUID. So I need to be able to know the UUID of a player, given the player's username and the time at which the player was known to have that username.

This is a critical, breaking change that was introduced to the API without any warning. I recognize that Mojang has a lot on their plate, especially with the upcoming account migration. Can we get a confirmation from staff that they, at least, intend to bring this back?

Unfortunately, I don't think they plan on bringing this back. They have been migrating parts of their API over to minecraftservices.com without any apparent warning, and there seems to be no documentation for the new API. Kind of annoying that they decided to break the original API as well. I've tried contacting their support in regards to this issue and the changes coming with the new API, both were met with links to the FAQ. Hopefully, Mojang comes out with something as they further deprecate the old API.

Dinnerbone himself has discussed this endpoint on Twitter in the past (see https://twitter.com/dinnerbone/status/554739042529849345).  I see no reason for it to be removed. No update in almost a month from Mojang staff.

While I'm at it, the fact that there is no notice whenever an API update occurs is a pet peeve of mine. If Mojang deprecates something it's up to the user to figure it out. We're not given any notice of that. It would be nice for API changelogs to be released whenever there's a new version or update. Especially considering that the entire API changed recently due to the MSA migration, and lots of old tools and programs will most likely stop working. How are we supposed to find the equivalent endpoints on the new API?

Has been more than 2 months and no update. Is there any confirmation that this is even on the roadmap for the future, or if you do not plan to fix this, just close the issue -  no point keeping this issue open if there are no plans to fix it.

Unfortunaly there is no 100%- complementary API for this available as others have alreay noted. The priority of this issue is wrong!

Do we have the ability to bump this to maximum priority? This feature has been broken in production for months and has no workarounds short of scraping data from third party websites. We would appreciate confirmation that this is on the roadmap.

Thanks to whoever added a note on the API wiki page that this feature is broken.

Is this going to be fixed soon or is it going to remain this way?

Any news on this?

As Ined mentioned in WEB-13,

We no longer support the at parameter for this endpoint.

If that is the case, this issue should be closed.

This is one of the biggest and most serious bugs on Mojira. It promotes inequality between API users like no other. Large databases such as NameMC can still effortlessly provide an overview of previous holders of names. This is in great contrast to the fact that smaller users cannot even historically match a single name. This API interface was created with an idea in mind, but now that idea is degenerating into a shadow of the glory days.

If this bug is not fixed, the further development of the Minecraft community will be set back by decades.

In the end, all I can say is: Fixing bugs is what Mojira is all about; that's what Mojira is for. Let's see how they do.