diff --git a/index-scheduler/src/index_mapper/mod.rs b/index-scheduler/src/index_mapper/mod.rs
index 14908120c..3cccb5a69 100644
--- a/index-scheduler/src/index_mapper/mod.rs
+++ b/index-scheduler/src/index_mapper/mod.rs
@@ -108,8 +108,10 @@ pub struct IndexStats {
     /// Association of every field name with the number of times it occurs in the documents.
     pub field_distribution: FieldDistribution,
     /// Creation date of the index.
+    #[serde(with = "time::serde::rfc3339")]
     pub created_at: OffsetDateTime,
     /// Date of the last update of the index.
+    #[serde(with = "time::serde::rfc3339")]
     pub updated_at: OffsetDateTime,
 }