diff --git a/api/oss/src/services/db_manager.py b/api/oss/src/services/db_manager.py
index 643d3712de..5e5a60b6d0 100644
--- a/api/oss/src/services/db_manager.py
+++ b/api/oss/src/services/db_manager.py
@@ -982,7 +982,9 @@ async def check_if_user_exists_and_create_organization(user_email: str):
 
 
 async def check_if_user_invitation_exists(email: str, organization_id: str):
-    """Check if a user invitation with the given email and organization_id exists."""
+    """Check if a user invitation with the given email and organization_id exists.
+    Email comparison is case-insensitive to handle SuperTokens email normalization.
+    """
 
     project_db = await get_project_by_organization_id(organization_id=organization_id)
     if not project_db:
@@ -990,9 +992,9 @@ async def check_if_user_invitation_exists(email: str, organization_id: str):
 
     async with engine.core_session() as session:
         result = await session.execute(
-            select(InvitationDB).filter_by(
-                email=email,
-                project_id=project_db.id,
+            select(InvitationDB).where(
+                func.lower(InvitationDB.email) == func.lower(email),
+                InvitationDB.project_id == project_db.id,
             )
         )
         user_invitation = result.scalars().first()
@@ -1131,6 +1133,7 @@ async def delete_accounts() -> None:
 
 async def create_accounts(payload: dict) -> UserDB:
     """Create a new account in the database.
+    Email is normalized to lowercase to match SuperTokens behavior.
 
     Args:
         payload (dict): The payload to create the user
@@ -1142,8 +1145,12 @@ async def create_accounts(payload: dict) -> UserDB:
     # pop required fields for organization & workspace creation
     organization_id = payload.pop("organization_id")
 
+    # Normalize email to lowercase to match SuperTokens behavior
+    normalized_email = payload["email"].lower()
+    payload["email"] = normalized_email
+
     # create user
-    user_info = {**payload, "username": payload["email"].split("@")[0]}
+    user_info = {**payload, "username": normalized_email.split("@")[0]}
     user_db = await user_service.create_new_user(payload=user_info)
 
     # only update organization to have user_db as its "owner" if it does not yet have one
@@ -1161,7 +1168,7 @@ async def create_accounts(payload: dict) -> UserDB:
 
     # update user invitation in the case the user was invited
     invitation = await get_project_invitation_by_email(
-        project_id=str(project_db.id), email=payload["email"]
+        project_id=str(project_db.id), email=normalized_email
     )
     if invitation is not None:
         await update_invitation(
@@ -1370,6 +1377,7 @@ async def get_workspaces() -> List[WorkspaceDB]:
 
 async def remove_user_from_workspace(project_id: str, email: str):
     """Remove a user from a workspace.
+    Email comparison is case-insensitive to handle SuperTokens email normalization.
 
     Args:
         project_id (str): The ID of the project
@@ -1461,6 +1469,7 @@ async def get_user_with_id(user_id: str) -> UserDB:
 async def get_user_with_email(email: str):
     """
     Retrieves a user from the database based on their email address.
+    Email comparison is case-insensitive to handle SuperTokens email normalization.
 
     Args:
         email (str): The email address of the user to retrieve.
@@ -1480,7 +1489,9 @@ async def get_user_with_email(email: str):
         raise Exception("Please provide a valid email address")
 
     async with engine.core_session() as session:
-        result = await session.execute(select(UserDB).filter_by(email=email))
+        result = await session.execute(
+            select(UserDB).where(func.lower(UserDB.email) == func.lower(email))
+        )
         user = result.scalars().first()
         return user
 
@@ -1625,6 +1636,7 @@ async def get_default_project_id_from_workspace(
 
 async def get_project_invitation_by_email(project_id: str, email: str) -> InvitationDB:
     """Get project invitation by project ID and email.
+    Email comparison is case-insensitive to handle SuperTokens email normalization.
 
     Args:
         project_id (str): The ID of the project.
@@ -1636,8 +1648,9 @@ async def get_project_invitation_by_email(project_id: str, email: str) -> Invita
 
     async with engine.core_session() as session:
         result = await session.execute(
-            select(InvitationDB).filter_by(
-                project_id=uuid.UUID(project_id), email=email
+            select(InvitationDB).where(
+                InvitationDB.project_id == uuid.UUID(project_id),
+                func.lower(InvitationDB.email) == func.lower(email)
             )
         )
         invitation = result.scalars().first()
@@ -1773,6 +1786,7 @@ async def get_project_invitation_by_token_and_email(
     project_id: str, token: str, email: str
 ) -> InvitationDB:
     """Get project invitation by project ID, token and email.
+    Email comparison is case-insensitive to handle SuperTokens email normalization.
 
     Args:
         project_id (str): The ID of the project.
@@ -1785,8 +1799,10 @@ async def get_project_invitation_by_token_and_email(
 
     async with engine.core_session() as session:
         result = await session.execute(
-            select(InvitationDB).filter_by(
-                project_id=uuid.UUID(project_id), token=token, email=email
+            select(InvitationDB).where(
+                InvitationDB.project_id == uuid.UUID(project_id),
+                InvitationDB.token == token,
+                func.lower(InvitationDB.email) == func.lower(email)
             )
         )
         invitation = result.scalars().first()
diff --git a/api/oss/src/services/organization_service.py b/api/oss/src/services/organization_service.py
index 030ce6bd3f..e945194493 100644
--- a/api/oss/src/services/organization_service.py
+++ b/api/oss/src/services/organization_service.py
@@ -18,6 +18,7 @@ def generate_invitation_token(token_length: int = 16):
 async def check_existing_invitation(project_id: str, email: str):
     """
     Checks if there is an existing invitation for a given project and email address.
+    Email is normalized to lowercase to match SuperTokens behavior.
 
     Args:
         project_id (str): The ID of the project for which the invitation is being checked.
@@ -26,14 +27,17 @@ async def check_existing_invitation(project_id: str, email: str):
     Returns:
     - invitation (InvitationDB): The existing invitation if it is valid and not expired. Otherwise, returns None.
     """
+    
+    # Normalize email to lowercase to match SuperTokens behavior
+    normalized_email = email.lower()
 
     invitation = await db_manager.get_project_invitation_by_email(
-        project_id=project_id, email=email
+        project_id=project_id, email=normalized_email
     )
     if (
         invitation is not None
         and not invitation.used
-        and invitation.email == email
+        and invitation.email.lower() == normalized_email
         and str(invitation.project_id) == project_id
     ):
         if invitation.expiration_date > datetime.now(timezone.utc):
@@ -50,6 +54,7 @@ async def check_existing_invitation(project_id: str, email: str):
 async def check_valid_invitation(project_id: str, email: str, token: str):
     """
     Check if a project invitation is valid for a given user and token.
+    Email is normalized to lowercase to match SuperTokens behavior.
 
     Args:
         project_id (str): The ID of the project for which the invitation is being checked.
@@ -60,9 +65,12 @@ async def check_valid_invitation(project_id: str, email: str, token: str):
         InvitationDB or None: Returns the invitation object if it's valid and not expired.
                               Returns None if the invitation is not found or has expired.
     """
+    
+    # Normalize email to lowercase to match SuperTokens behavior
+    normalized_email = email.lower()
 
     invitation = await db_manager.get_project_invitation_by_token_and_email(
-        project_id, token, email
+        project_id, token, normalized_email
     )
     if invitation is not None and invitation.expiration_date > datetime.now(
         timezone.utc
@@ -135,6 +143,7 @@ async def send_invitation_email(
 async def create_invitation(role: str, project_id: str, email: str):
     """
     Creates a new invitation for a user to join an organization.
+    Email is normalized to lowercase to match SuperTokens behavior.
 
     Args:
         role (str): The role to be assigned to the invited user in the organization.
@@ -148,12 +157,15 @@ async def create_invitation(role: str, project_id: str, email: str):
 
     token = generate_invitation_token()
     expiration_date = datetime.now(timezone.utc) + timedelta(days=7)
+    
+    # Normalize email to lowercase to match SuperTokens behavior
+    normalized_email = email.lower()
 
     invitation = await db_manager.create_user_invitation_to_organization(
         project_id=project_id,
         token=token,
         role=role,
-        email=email,
+        email=normalized_email,
         expiration_date=expiration_date,
     )
     return invitation
@@ -178,8 +190,11 @@ async def invite_user_to_organization(
 
     user_performing_action = await db_manager.get_user_with_id(user_id=user_id)
 
+    # Normalize email to lowercase to match SuperTokens behavior
+    normalized_email = payload.email.lower()
+    
     # Check that the user is not inviting themselves
-    if payload.email == user_performing_action.email:
+    if normalized_email == user_performing_action.email.lower():
         raise HTTPException(
             status_code=400,
             detail="You cannot invite yourself to a workspace",
@@ -187,7 +202,7 @@ async def invite_user_to_organization(
 
     # Check if the user is already a member of the workspace
     existing_invitation, existing_role = await check_existing_invitation(
-        project_id=project_id, email=payload.email
+        project_id=project_id, email=normalized_email
     )
     if existing_invitation or existing_role:
         raise HTTPException(
@@ -196,12 +211,12 @@ async def invite_user_to_organization(
         )
 
     # Create a new invitation since user hasn't been invited
-    invitation = await create_invitation("editor", project_id, payload.email)
+    invitation = await create_invitation("editor", project_id, normalized_email)
 
     # Get project by id
     project_db = await db_manager.get_project_by_id(project_id=project_id)
 
-    # Send the invitation email
+    # Send the invitation email (use original email for display purposes)
     send_email = await send_invitation_email(
         payload.email,
         invitation.token,  # type: ignore
@@ -240,15 +255,18 @@ async def resend_user_organization_invite(
 
     user_performing_action = await db_manager.get_user_with_id(user_id=user_id)
 
+    # Normalize email to lowercase to match SuperTokens behavior
+    normalized_email = payload.email.lower()
+
     # Check if the email address already has a valid, unused invitation for the workspace
     existing_invitation, existing_role = await check_existing_invitation(
-        project_id, payload.email
+        project_id, normalized_email
     )
     if existing_invitation:
         invitation = existing_invitation
     elif existing_role:
         # Create a new invitation
-        invitation = await create_invitation("editor", project_id, payload.email)
+        invitation = await create_invitation("editor", project_id, normalized_email)
 
     # Get project by id
     project_db = await db_manager.get_project_by_id(project_id=project_id)