diff --git a/includes/api/ApiAMCreateAccount.php b/includes/api/ApiAMCreateAccount.php
index 162bc02c696..bcf52b05c4b 100644
--- a/includes/api/ApiAMCreateAccount.php
+++ b/includes/api/ApiAMCreateAccount.php
@@ -22,6 +22,7 @@
 
 use MediaWiki\Auth\AuthenticationResponse;
 use MediaWiki\Auth\AuthManager;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Create an account with AuthManager
@@ -63,8 +64,8 @@ class ApiAMCreateAccount extends ApiBase {
 			}
 		}
 
-		$helper = new ApiAuthManagerHelper( $this );
-		$manager = AuthManager::singleton();
+		$manager = MediaWikiServices::getInstance()->getAuthManager();
+		$helper = new ApiAuthManagerHelper( $this, $manager );
 
 		// Make sure it's possible to create accounts
 		if ( !$manager->canCreateAccounts() ) {
diff --git a/includes/api/ApiAuthManagerHelper.php b/includes/api/ApiAuthManagerHelper.php
index dad9805fb48..14137863442 100644
--- a/includes/api/ApiAuthManagerHelper.php
+++ b/includes/api/ApiAuthManagerHelper.php
@@ -26,6 +26,7 @@ use MediaWiki\Auth\AuthenticationResponse;
 use MediaWiki\Auth\AuthManager;
 use MediaWiki\Auth\CreateFromLoginAuthenticationRequest;
 use MediaWiki\Logger\LoggerFactory;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Helper class for AuthManager-using API modules. Intended for use via
@@ -41,23 +42,29 @@ class ApiAuthManagerHelper {
 	/** @var string Message output format */
 	private $messageFormat;
 
+	/** @var AuthManager */
+	private $authManager;
+
 	/**
 	 * @param ApiBase $module API module, for context and parameters
+	 * @param AuthManager|null $authManager
 	 */
-	public function __construct( ApiBase $module ) {
+	public function __construct( ApiBase $module, AuthManager $authManager = null ) {
 		$this->module = $module;
 
 		$params = $module->extractRequestParams();
 		$this->messageFormat = $params['messageformat'] ?? 'wikitext';
+		$this->authManager = $authManager ?: MediaWikiServices::getInstance()->getAuthManager();
 	}
 
 	/**
 	 * Static version of the constructor, for chaining
 	 * @param ApiBase $module API module, for context and parameters
+	 * @param AuthManager|null $authManager
 	 * @return ApiAuthManagerHelper
 	 */
-	public static function newForModule( ApiBase $module ) {
-		return new self( $module );
+	public static function newForModule( ApiBase $module, AuthManager $authManager = null ) {
+		return new self( $module, $authManager );
 	}
 
 	/**
@@ -97,7 +104,7 @@ class ApiAuthManagerHelper {
 	 * @throws ApiUsageException
 	 */
 	public function securitySensitiveOperation( $operation ) {
-		$status = AuthManager::singleton()->securitySensitiveOperationStatus( $operation );
+		$status = $this->authManager->securitySensitiveOperationStatus( $operation );
 		switch ( $status ) {
 			case AuthManager::SEC_OK:
 				return;
@@ -137,8 +144,7 @@ class ApiAuthManagerHelper {
 	public function loadAuthenticationRequests( $action ) {
 		$params = $this->module->extractRequestParams();
 
-		$manager = AuthManager::singleton();
-		$reqs = $manager->getAuthenticationRequests( $action, $this->module->getUser() );
+		$reqs = $this->authManager->getAuthenticationRequests( $action, $this->module->getUser() );
 
 		// Filter requests, if requested to do so
 		$wantedRequests = null;
diff --git a/includes/api/ApiChangeAuthenticationData.php b/includes/api/ApiChangeAuthenticationData.php
index aa64444fd8d..f8bacce2abb 100644
--- a/includes/api/ApiChangeAuthenticationData.php
+++ b/includes/api/ApiChangeAuthenticationData.php
@@ -21,6 +21,7 @@
  */
 
 use MediaWiki\Auth\AuthManager;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Change authentication data with AuthManager
@@ -38,8 +39,8 @@ class ApiChangeAuthenticationData extends ApiBase {
 			$this->dieWithError( 'apierror-mustbeloggedin-changeauthenticationdata', 'notloggedin' );
 		}
 
-		$helper = new ApiAuthManagerHelper( $this );
-		$manager = AuthManager::singleton();
+		$manager = MediaWikiServices::getInstance()->getAuthManager();
+		$helper = new ApiAuthManagerHelper( $this, $manager );
 
 		// Check security-sensitive operation status
 		$helper->securitySensitiveOperation( 'ChangeCredentials' );
diff --git a/includes/api/ApiClientLogin.php b/includes/api/ApiClientLogin.php
index 44f5a85947c..2047d8f5dd1 100644
--- a/includes/api/ApiClientLogin.php
+++ b/includes/api/ApiClientLogin.php
@@ -23,6 +23,7 @@
 use MediaWiki\Auth\AuthenticationResponse;
 use MediaWiki\Auth\AuthManager;
 use MediaWiki\Auth\CreateFromLoginAuthenticationRequest;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Log in to the wiki with AuthManager
@@ -64,8 +65,8 @@ class ApiClientLogin extends ApiBase {
 			}
 		}
 
-		$helper = new ApiAuthManagerHelper( $this );
-		$manager = AuthManager::singleton();
+		$manager = MediaWikiServices::getInstance()->getAuthManager();
+		$helper = new ApiAuthManagerHelper( $this, $manager );
 
 		// Make sure it's possible to log in
 		if ( !$manager->canAuthenticateNow() ) {
diff --git a/includes/api/ApiLinkAccount.php b/includes/api/ApiLinkAccount.php
index 3bd203a90ed..f6fe36bd6d8 100644
--- a/includes/api/ApiLinkAccount.php
+++ b/includes/api/ApiLinkAccount.php
@@ -22,6 +22,7 @@
 
 use MediaWiki\Auth\AuthenticationResponse;
 use MediaWiki\Auth\AuthManager;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Link an account with AuthManager
@@ -67,8 +68,8 @@ class ApiLinkAccount extends ApiBase {
 			}
 		}
 
-		$helper = new ApiAuthManagerHelper( $this );
-		$manager = AuthManager::singleton();
+		$manager = MediaWikiServices::getInstance()->getAuthManager();
+		$helper = new ApiAuthManagerHelper( $this, $manager );
 
 		// Check security-sensitive operation status
 		$helper->securitySensitiveOperation( 'LinkAccounts' );
diff --git a/includes/api/ApiLogin.php b/includes/api/ApiLogin.php
index 1666be9e8e2..ee5b366b009 100644
--- a/includes/api/ApiLogin.php
+++ b/includes/api/ApiLogin.php
@@ -25,6 +25,7 @@ use MediaWiki\Auth\AuthenticationRequest;
 use MediaWiki\Auth\AuthenticationResponse;
 use MediaWiki\Auth\AuthManager;
 use MediaWiki\Logger\LoggerFactory;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Unit to authenticate log-in attempts to the current wiki.
@@ -148,7 +149,7 @@ class ApiLogin extends ApiBase {
 
 		if ( $authRes === false ) {
 			// Simplified AuthManager login, for backwards compatibility
-			$manager = AuthManager::singleton();
+			$manager = MediaWikiServices::getInstance()->getAuthManager();
 			$reqs = AuthenticationRequest::loadRequestsFromSubmission(
 				$manager->getAuthenticationRequests( AuthManager::ACTION_LOGIN, $this->getUser() ),
 				[
@@ -158,7 +159,7 @@ class ApiLogin extends ApiBase {
 					'rememberMe' => true,
 				]
 			);
-			$res = AuthManager::singleton()->beginAuthentication( $reqs, 'null:' );
+			$res = $manager->beginAuthentication( $reqs, 'null:' );
 			switch ( $res->status ) {
 				case AuthenticationResponse::PASS:
 					if ( $this->getConfig()->get( 'EnableBotPasswords' ) ) {
diff --git a/includes/api/ApiQueryAuthManagerInfo.php b/includes/api/ApiQueryAuthManagerInfo.php
index d23d8988f3f..29467ef863d 100644
--- a/includes/api/ApiQueryAuthManagerInfo.php
+++ b/includes/api/ApiQueryAuthManagerInfo.php
@@ -22,6 +22,7 @@
  */
 
 use MediaWiki\Auth\AuthManager;
+use MediaWiki\MediaWikiServices;
 
 /**
  * A query action to return meta information about AuthManager state.
@@ -36,9 +37,8 @@ class ApiQueryAuthManagerInfo extends ApiQueryBase {
 
 	public function execute() {
 		$params = $this->extractRequestParams();
-		$helper = new ApiAuthManagerHelper( $this );
-
-		$manager = AuthManager::singleton();
+		$manager = MediaWikiServices::getInstance()->getAuthManager();
+		$helper = new ApiAuthManagerHelper( $this, $manager );
 		$ret = [
 			'canauthenticatenow' => $manager->canAuthenticateNow(),
 			'cancreateaccounts' => $manager->canCreateAccounts(),
diff --git a/includes/api/ApiQueryUsers.php b/includes/api/ApiQueryUsers.php
index 2907da5c688..1766bff81fb 100644
--- a/includes/api/ApiQueryUsers.php
+++ b/includes/api/ApiQueryUsers.php
@@ -21,6 +21,7 @@
  */
 
 use MediaWiki\Block\DatabaseBlock;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Query module to get information about a list of users
@@ -297,7 +298,8 @@ class ApiQueryUsers extends ApiQueryBase {
 					} else {
 						$data[$u]['missing'] = true;
 						if ( isset( $this->prop['cancreate'] ) ) {
-							$status = MediaWiki\Auth\AuthManager::singleton()->canCreateAccount( $u );
+							$status = MediaWikiServices::getInstance()->getAuthManager()
+								->canCreateAccount( $u );
 							$data[$u]['cancreate'] = $status->isGood();
 							if ( !$status->isGood() ) {
 								$data[$u]['cancreateerror'] = $this->getErrorFormatter()->arrayFromStatus( $status );
diff --git a/includes/api/ApiRemoveAuthenticationData.php b/includes/api/ApiRemoveAuthenticationData.php
index eeed94d6509..3354bbaa27f 100644
--- a/includes/api/ApiRemoveAuthenticationData.php
+++ b/includes/api/ApiRemoveAuthenticationData.php
@@ -22,6 +22,7 @@
 
 use MediaWiki\Auth\AuthenticationRequest;
 use MediaWiki\Auth\AuthManager;
+use MediaWiki\MediaWikiServices;
 
 /**
  * Remove authentication data from AuthManager
@@ -50,10 +51,11 @@ class ApiRemoveAuthenticationData extends ApiBase {
 		}
 
 		$params = $this->extractRequestParams();
-		$manager = AuthManager::singleton();
+		$manager = MediaWikiServices::getInstance()->getAuthManager();
 
 		// Check security-sensitive operation status
-		ApiAuthManagerHelper::newForModule( $this )->securitySensitiveOperation( $this->operation );
+		ApiAuthManagerHelper::newForModule( $this, $manager )
+			->securitySensitiveOperation( $this->operation );
 
 		// Fetch the request. No need to load from the request, so don't use
 		// ApiAuthManagerHelper's method.
diff --git a/includes/api/ApiValidatePassword.php b/includes/api/ApiValidatePassword.php
index d43846a6f6b..ec54504e532 100644
--- a/includes/api/ApiValidatePassword.php
+++ b/includes/api/ApiValidatePassword.php
@@ -1,6 +1,6 @@
 <?php
 
-use MediaWiki\Auth\AuthManager;
+use MediaWiki\MediaWikiServices;
 use MediaWiki\ParamValidator\TypeDef\UserDef;
 
 /**
@@ -24,7 +24,9 @@ class ApiValidatePassword extends ApiBase {
 				);
 			}
 
-			if ( !$user->isAnon() || AuthManager::singleton()->userExists( $user->getName() ) ) {
+			if ( !$user->isAnon() ||
+				MediaWikiServices::getInstance()->getAuthManager()->userExists( $user->getName() )
+			) {
 				$this->dieWithError( 'userexists' );
 			}