diff --git a/actions/products.ts b/actions/products.ts
index f238058..9a0856b 100644
--- a/actions/products.ts
+++ b/actions/products.ts
@@ -366,6 +366,7 @@ export async function removeProductMemberAction(productId: string, memberId: str
 export async function leaveProductAction(productId: string) {
   const session = await getSession()
   if (!session.userId) return { error: 'Niet ingelogd' }
+  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }
 
   await prisma.$transaction([
     prisma.user.updateMany({
diff --git a/actions/todos.ts b/actions/todos.ts
index 3c68da9..7720eb4 100644
--- a/actions/todos.ts
+++ b/actions/todos.ts
@@ -47,6 +47,7 @@ export async function createTodoAction(_prevState: unknown, formData: FormData)
 export async function toggleTodoAction(id: string, done: boolean) {
   const session = await getSession()
   if (!session.userId) return { error: 'Niet ingelogd' }
+  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }
 
   const todo = await prisma.todo.findFirst({ where: { id, user_id: session.userId } })
   if (!todo) return { error: 'Todo niet gevonden' }
@@ -59,6 +60,7 @@ export async function toggleTodoAction(id: string, done: boolean) {
 export async function archiveCompletedTodosAction() {
   const session = await getSession()
   if (!session.userId) return { error: 'Niet ingelogd' }
+  if (session.isDemo) return { error: 'Niet beschikbaar in demo-modus' }
 
   await prisma.todo.updateMany({
     where: { user_id: session.userId, done: true, archived: false },