diff --git a/MatrixSDK/JSONModels/MXEvent.h b/MatrixSDK/JSONModels/MXEvent.h
index 6905acf501..3a9a65a6f4 100644
--- a/MatrixSDK/JSONModels/MXEvent.h
+++ b/MatrixSDK/JSONModels/MXEvent.h
@@ -278,6 +278,12 @@ FOUNDATION_EXPORT NSString *const kMXMessageContentKeyExtensibleAssetMSC3488;
 FOUNDATION_EXPORT NSString *const kMXMessageContentKeyExtensibleAssetType;
 FOUNDATION_EXPORT NSString *const kMXMessageContentKeyExtensibleAssetTypeUser;
 
+// Join Rules
+
+FOUNDATION_EXPORT NSString *const kMXJoinRulesContentKeyAllow;
+FOUNDATION_EXPORT NSString *const kMXJoinRulesContentKeyType;
+FOUNDATION_EXPORT NSString *const kMXJoinRulesContentKeyRoomId;
+
 /**
  The internal event state used to handle the different steps of the event sending.
  */
diff --git a/MatrixSDK/JSONModels/MXEvent.m b/MatrixSDK/JSONModels/MXEvent.m
index ea32e89714..3f40da63cd 100644
--- a/MatrixSDK/JSONModels/MXEvent.m
+++ b/MatrixSDK/JSONModels/MXEvent.m
@@ -187,6 +187,12 @@
 NSString *const kMXMessageContentKeyExtensibleAssetType = @"type";
 NSString *const kMXMessageContentKeyExtensibleAssetTypeUser = @"m.self";
 
+// Join Rules
+
+NSString *const kMXJoinRulesContentKeyAllow = @"allow";
+NSString *const kMXJoinRulesContentKeyType = @"type";
+NSString *const kMXJoinRulesContentKeyRoomId = @"room_id";
+
 #pragma mark - MXEvent
 @interface MXEvent ()
 {
diff --git a/MatrixSDK/Space/MXRoomAliasAvailabilityChecker.swift b/MatrixSDK/Space/MXRoomAliasAvailabilityChecker.swift
index 6091b0ccb9..887e5f5abb 100644
--- a/MatrixSDK/Space/MXRoomAliasAvailabilityChecker.swift
+++ b/MatrixSDK/Space/MXRoomAliasAvailabilityChecker.swift
@@ -48,7 +48,7 @@ public class MXRoomAliasAvailabilityChecker {
             return nil
         }
         
-        let fullAlias = aliasLocalPart.fullLocalAlias(with: session)
+        let fullAlias = MXTools.fullLocalAlias(from: aliasLocalPart, with: session)
         guard aliasLocalPart.filter({ !validAliasCharacters.contains($0) }).count == 0 else {
             completion(.invalid)
             return nil
@@ -66,22 +66,40 @@ public class MXRoomAliasAvailabilityChecker {
     }
 }
 
-public extension String {
+public extension MXTools {
     /// Generates a full local alias String (e.g. "#my_alias:example.org" for the string "my_alias")
     /// - Parameters:
+    ///   - string: based string
     ///   - session: session used to retrieve the homeserver suffix
     /// - Returns:the full local alias String without checking the validity of the alias local part
-    func fullLocalAlias(with session: MXSession) -> String {
+    static func fullLocalAlias(from string: String, with session: MXSession) -> String {
         guard let homeserverSuffix = session.matrixRestClient.homeserverSuffix else {
-            return self
+            return string
         }
         
-        return "#\(self)\(homeserverSuffix)"
+        return "#\(string)\(homeserverSuffix)"
     }
     
     /// Generates a valid local alias part String by replacing unauthorised characters
+    /// - Parameters:
+    ///   - string: based string
     /// - Returns:a valid local alias part.
-    func toValidAliasLocalPart() -> String {
-        return lowercased().replacingOccurrences(of: " ", with: "-").filter { MXRoomAliasAvailabilityChecker.validAliasCharacters.contains($0) }
+    static func validAliasLocalPart(from string: String) -> String {
+        return string.lowercased().replacingOccurrences(of: " ", with: "-").filter { MXRoomAliasAvailabilityChecker.validAliasCharacters.contains($0) }
+    }
+    
+    /// Extract the valid local alias part String of the string ((e.g. "my_alias" for the string "#my_alias:example.org")
+    /// - Parameters:
+    ///   - string: based string
+    /// - Returns:the valid local alias part extracted from the string.
+    static func extractLocalAliasPart(from string: String) -> String {
+        var aliasPart = string
+        while aliasPart.starts(with: "#") {
+            aliasPart.removeFirst()
+        }
+        if let index = aliasPart.firstIndex(of: ":") {
+            aliasPart.removeSubrange(index ..< aliasPart.endIndex)
+        }
+        return aliasPart
     }
 }
diff --git a/MatrixSDKTests/MXRoomAliasAvailabilityCheckerResultTests.swift b/MatrixSDKTests/MXRoomAliasAvailabilityCheckerResultTests.swift
index 763df55808..b47fd3baac 100644
--- a/MatrixSDKTests/MXRoomAliasAvailabilityCheckerResultTests.swift
+++ b/MatrixSDKTests/MXRoomAliasAvailabilityCheckerResultTests.swift
@@ -15,6 +15,7 @@
 //
 
 import XCTest
+import MatrixSDK
 
 class MXRoomAliasAvailabilityCheckerResultTests: XCTestCase {
     
@@ -59,19 +60,19 @@ class MXRoomAliasAvailabilityCheckerResultTests: XCTestCase {
             }
             
             let aliasLocalPart = UUID().uuidString
-            var validAliasLocalPart = aliasLocalPart.toValidAliasLocalPart()
+            var validAliasLocalPart = MXTools.validAliasLocalPart(from: aliasLocalPart)
             
             XCTAssertEqual(aliasLocalPart.lowercased(), validAliasLocalPart)
             
-            var fullAlias = validAliasLocalPart.fullLocalAlias(with: session)
+            var fullAlias = MXTools.fullLocalAlias(from: validAliasLocalPart, with: session)
             XCTAssertEqual(fullAlias, "#\(validAliasLocalPart)\(session.matrixRestClient.homeserverSuffix!)")
             
             let invalidAliasLocalPart = "Some Invalid al;i{a|s"
-            validAliasLocalPart = invalidAliasLocalPart.toValidAliasLocalPart()
+            validAliasLocalPart = MXTools.validAliasLocalPart(from: invalidAliasLocalPart)
             
             XCTAssertEqual(validAliasLocalPart, "some-invalid-alias")
             
-            fullAlias = validAliasLocalPart.fullLocalAlias(with: session)
+            fullAlias = MXTools.fullLocalAlias(from: validAliasLocalPart, with: session)
             XCTAssertEqual(fullAlias, "#\(validAliasLocalPart)\(session.matrixRestClient.homeserverSuffix!)")
 
             expectation?.fulfill()
diff --git a/MatrixSDKTests/MXSpaceChildContentTests.swift b/MatrixSDKTests/MXSpaceChildContentTests.swift
index 096a990c95..3c3da30799 100644
--- a/MatrixSDKTests/MXSpaceChildContentTests.swift
+++ b/MatrixSDKTests/MXSpaceChildContentTests.swift
@@ -472,7 +472,7 @@ class MXSpaceChildContentTests: XCTestCase {
             }
             
             // Create space with default parameters
-            bobSession.spaceService.createSpace(withName: spaceName, topic: topic, isPublic: true, aliasLocalPart: "\(spaceName.toValidAliasLocalPart())-\(NSUUID().uuidString)", inviteArray: [aliceSession.myUserId]) { response in
+            bobSession.spaceService.createSpace(withName: spaceName, topic: topic, isPublic: true, aliasLocalPart: "\(MXTools.validAliasLocalPart(from: spaceName))-\(NSUUID().uuidString)", inviteArray: [aliceSession.myUserId]) { response in
                 switch response {
                 case .success(let space):
                     guard space.room != nil else {
diff --git a/MatrixSDKTests/MXSpaceServiceTest.swift b/MatrixSDKTests/MXSpaceServiceTest.swift
index 757fd02e6b..a8be833744 100644
--- a/MatrixSDKTests/MXSpaceServiceTest.swift
+++ b/MatrixSDKTests/MXSpaceServiceTest.swift
@@ -61,7 +61,7 @@ class MXSpaceServiceTest: XCTestCase {
         for spaceName in spaceNames {
             
             dispatchGroup.enter()
-            let alias = "\(spaceName.toValidAliasLocalPart())-\(NSUUID().uuidString)"
+            let alias = "\(MXTools.validAliasLocalPart(from: spaceName))-\(NSUUID().uuidString)"
             
             spaceService.createSpace(withName: spaceName, topic: nil, isPublic: true, aliasLocalPart: alias, inviteArray: nil) { (response) in
                                 
@@ -176,7 +176,7 @@ class MXSpaceServiceTest: XCTestCase {
             
             let expectedSpaceName = "mxSpace \(NSUUID().uuidString)"
             let expectedSpaceTopic = "Space topic"
-            let alias = expectedSpaceName.toValidAliasLocalPart()
+            let alias = MXTools.validAliasLocalPart(from: expectedSpaceName)
             
             // Create a public space
             spaceService.createSpace(withName: expectedSpaceName, topic: expectedSpaceTopic, isPublic: true, aliasLocalPart: alias, inviteArray: nil) { (response) in
diff --git a/changelog.d/5233.feature b/changelog.d/5233.feature
new file mode 100644
index 0000000000..5252dd10ef
--- /dev/null
+++ b/changelog.d/5233.feature
@@ -0,0 +1 @@
+MXRoomAliasAvailabilityChecker: added extractLocalAliasPart()
\ No newline at end of file