diff --git a/src/matrix/SessionContainer.js b/src/matrix/SessionContainer.js
index 2e64a2f6..0b917426 100644
--- a/src/matrix/SessionContainer.js
+++ b/src/matrix/SessionContainer.js
@@ -28,7 +28,7 @@ import {Sync, SyncStatus} from "./Sync.js";
 import {Session} from "./Session.js";
 import {PasswordLoginMethod} from "./login/PasswordLoginMethod";
 import {TokenLoginMethod} from "./login/TokenLoginMethod";
-import {SSOLoginHelper} from "./login/SSOLoginHelper.js";
+import {SSOLoginHelper} from "./login/SSOLoginHelper";
 import {getDehydratedDevice} from "./e2ee/Dehydration.js";
 
 export const LoadStatus = createEnum(
diff --git a/src/matrix/login/SSOLoginHelper.js b/src/matrix/login/SSOLoginHelper.ts
similarity index 80%
rename from src/matrix/login/SSOLoginHelper.js
rename to src/matrix/login/SSOLoginHelper.ts
index a15c8ef9..0fe3d6b8 100644
--- a/src/matrix/login/SSOLoginHelper.js
+++ b/src/matrix/login/SSOLoginHelper.ts
@@ -15,13 +15,15 @@ limitations under the License.
 */
 
 export class SSOLoginHelper{
-    constructor(homeserver) {
+    private _homeserver: string;
+
+    constructor(homeserver: string) {
         this._homeserver = homeserver;
     }
 
-    get homeserver() { return this._homeserver; }
+    get homeserver(): string { return this._homeserver; }
 
-    createSSORedirectURL(returnURL) {
+    createSSORedirectURL(returnURL: string): string {
         return `${this._homeserver}/_matrix/client/r0/login/sso/redirect?redirectUrl=${returnURL}`;
     }
 }