diff --git a/matrixgw_backend/src/controllers/matrix/matrix_event_controller.rs b/matrixgw_backend/src/controllers/matrix/matrix_event_controller.rs
index 7befb98..f6ab6e7 100644
--- a/matrixgw_backend/src/controllers/matrix/matrix_event_controller.rs
+++ b/matrixgw_backend/src/controllers/matrix/matrix_event_controller.rs
@@ -7,6 +7,8 @@ use matrix_sdk::Room;
 use matrix_sdk::deserialized_responses::{TimelineEvent, TimelineEventKind};
 use matrix_sdk::room::MessagesOptions;
 use matrix_sdk::room::edit::EditedContent;
+use matrix_sdk::ruma::events::reaction::ReactionEventContent;
+use matrix_sdk::ruma::events::relation::Annotation;
 use matrix_sdk::ruma::events::room::message::{
     RoomMessageEventContent, RoomMessageEventContentWithoutRelation,
 };
@@ -160,6 +162,28 @@ pub async fn set_text_content(
     })
 }
 
+#[derive(Deserialize)]
+struct EventReactionBody {
+    key: String,
+}
+
+pub async fn react_to_event(
+    client: MatrixClientExtractor,
+    path: web::Path<RoomIdInPath>,
+    event_path: web::Path<EventIdInPath>,
+) -> HttpResult {
+    let body = client.auth.decode_json_body::<EventReactionBody>()?;
+
+    let Some(room) = client.client.client.get_room(&path.room_id) else {
+        return Ok(HttpResponse::NotFound().json("Room not found!"));
+    };
+
+    let annotation = Annotation::new(event_path.event_id.to_owned(), body.key.to_owned());
+    room.send(ReactionEventContent::from(annotation)).await?;
+
+    Ok(HttpResponse::Accepted().finish())
+}
+
 pub async fn redact_event(
     client: MatrixClientExtractor,
     path: web::Path<RoomIdInPath>,
diff --git a/matrixgw_backend/src/main.rs b/matrixgw_backend/src/main.rs
index 6814d0f..f79d018 100644
--- a/matrixgw_backend/src/main.rs
+++ b/matrixgw_backend/src/main.rs
@@ -177,6 +177,10 @@ async fn main() -> std::io::Result<()> {
                 "/api/matrix/room/{room_id}/event/{event_id}/set_text_content",
                 web::post().to(matrix_event_controller::set_text_content),
             )
+            .route(
+                "/api/matrix/room/{room_id}/event/{event_id}/react",
+                web::post().to(matrix_event_controller::react_to_event),
+            )
             .route(
                 "/api/matrix/room/{room_id}/event/{event_id}",
                 web::delete().to(matrix_event_controller::redact_event),