diff --git a/bindings/matrix-sdk-ffi/src/api.udl b/bindings/matrix-sdk-ffi/src/api.udl
index 76e2de280..dabf4c60d 100644
--- a/bindings/matrix-sdk-ffi/src/api.udl
+++ b/bindings/matrix-sdk-ffi/src/api.udl
@@ -8,10 +8,6 @@ callback interface NotificationDelegate {
     void did_receive_notification(NotificationItem notification);
 };
 
-interface AuthenticationService {};
-interface Span {};
-interface NotificationService {};
-
 dictionary NotificationItem {
     TimelineEvent event;
     string room_id;
diff --git a/bindings/matrix-sdk-ffi/src/authentication_service.rs b/bindings/matrix-sdk-ffi/src/authentication_service.rs
index 19aa92383..fae7387d8 100644
--- a/bindings/matrix-sdk-ffi/src/authentication_service.rs
+++ b/bindings/matrix-sdk-ffi/src/authentication_service.rs
@@ -11,6 +11,7 @@ use zeroize::Zeroize;
 use super::{client::Client, client_builder::ClientBuilder, RUNTIME};
 use crate::error::ClientError;
 
+#[derive(uniffi::Object)]
 pub struct AuthenticationService {
     base_path: String,
     passphrase: Option<String>,
diff --git a/bindings/matrix-sdk-ffi/src/notification_service.rs b/bindings/matrix-sdk-ffi/src/notification_service.rs
index 16cf23fbf..64f3d8977 100644
--- a/bindings/matrix-sdk-ffi/src/notification_service.rs
+++ b/bindings/matrix-sdk-ffi/src/notification_service.rs
@@ -51,6 +51,7 @@ impl NotificationItem {
 }
 
 #[allow(dead_code)]
+#[derive(uniffi::Object)]
 pub struct NotificationService {
     base_path: String,
     user_id: String,
diff --git a/bindings/matrix-sdk-ffi/src/tracing.rs b/bindings/matrix-sdk-ffi/src/tracing.rs
index d85ce08ee..c530f33f3 100644
--- a/bindings/matrix-sdk-ffi/src/tracing.rs
+++ b/bindings/matrix-sdk-ffi/src/tracing.rs
@@ -95,6 +95,7 @@ fn span_or_event_enabled(callsite: &'static DefaultCallsite) -> bool {
     }
 }
 
+#[derive(uniffi::Object)]
 pub struct Span(tracing::Span);
 
 #[uniffi::export]