Single user login

Single user login (sometimes referred to as CentralAuth) is Miraheze's unified login system.

Once you create an account on one Miraheze wiki, you can use it on all wikis without having to create a new account or login again. Your username also cannot be used by someone else on a different Miraheze wiki once you've registered it as it is reserved just for you on all wikis.

Overview
When you make an account on Miraheze, you only need one account for all wikis. This means that once you create an account on any of our wikis, you can use it on any other wiki without having to sign up again. Your username is unique to you, and you can use your login details to access any Miraheze wiki.

Miraheze uses CentralAuth as its single user login software. CentralAuth was created by the Wikimedia Foundation and is the same software used on their wikis.

When you make an account on a wiki, there are two types of accounts created: global and local. A global account is like your master account, where you keep your important information like your email, password, and two-factor authentication status. You make this account when you first sign up for any wiki. A local account is a copy of your account that belongs to a specific wiki. It's controlled by your global account, and it gets all of its information, like your email and password, from your global account.

Even though your account works on all Miraheze wikis, it's not automatically visible on every wiki. If you haven't visited a specific wiki yet, the wiki won't know that you exist. If you try to find yourself using Special:ListUsers or Special:Contributions, you might get an error saying that you don't exist. This is because MediaWiki doesn't fully support the idea of a global account (it's being worked on by MediaWiki developers). When you visit a new wiki for the first time, CentralAuth creates a local copy of your account (called a local account) based on your global account. This happens very quickly and you won't even notice it. After this, the wiki will realize who you are, and you'll appear on the user list and other pages.

But even if there's no local copy of your account on a specific wiki, MediaWiki still reserves your username on that wiki. This means no one else can use it to impersonate you. If someone tries to sign up using your username on a wiki where you don't have a local account yet, the software will stop them and refuse to sign them up.

Once you've visited a wiki for the first time, you'll be automatically logged into it when signing in to Miraheze.

Benefits

 * Easy login - With a single login, users can access all Miraheze wikis without having to create multiple accounts or having to re-login multiple times. Your username is also reserved on all wikis, so no one can impersonate you on another wiki.
 * Easy password recovery - If you lose your password or need to reset it, you can do so from any wiki and change it globally on all wikis. No need to change it individually on each wiki.
 * Global preferences and CSS/JS - You can set global user preferences which apply to all wikis instead of having to set certain preferences over and over again on each wiki; these global preferences can be later overridden on a wiki if you wish. For power users, you can also create custom global CSS or JavaScript which applies to you on all wikis.
 * Global user page - You can create a global user page on Login Wiki which shows up on all wikis where you have no local user page created. Whenever you update this user page, it'll also change on all wikis. This can help save you time and effort in having to create user pages and then update each one when something changes.
 * Unified notifications - No need to check each individual wiki you edit to see if you have new messages or notifications. You can check all your notifications from any wiki via Special:Notifications.

Can I unlink my wiki from this system?
No. Unlinking a wiki from the system might confuse users who try to log in to your wiki using their global Miraheze credentials. Additionally, due to technical impediments, things such as passwords aren't stored in your wiki's database but instead are stored on the global user database, meaning that unlinking a wiki from the system would leave accounts broken.

How do I rename users on my wiki?
Since user accounts are shared on all wikis, they have to have one username on all wikis. To prevent administrators on one wiki from being able to abuse the rename system and rename whatever user they like across all wikis, only Stewards can rename users. For more information, see Changing username. Requests for global renames typically take less than a day to process and once approved, they usually take only a few minutes to finish.

Can I reset passwords for my users or disable their two-factor authentication?
No. If administrators could do this then anyone would be able to change your password, as accounts are shared across all wikis.

Can I use a login system that is not CentralAuth?
No. As mentioned previously, unlinking wikis from CentralAuth might break local accounts. Additionally, Miraheze staff would be unable to access the wiki to enable restricted settings or do things like Checkusers or Oversights, or help debug any technical issues you face.