diff --git a/async-nats/src/service/endpoint.rs b/async-nats/src/service/endpoint.rs
index 7c17a97ae..6f3b4fdf0 100644
--- a/async-nats/src/service/endpoint.rs
+++ b/async-nats/src/service/endpoint.rs
@@ -130,7 +130,7 @@ pub(crate) struct Inner {
     /// Last error that occurred.
     pub(crate) last_error: Option<error::Error>,
     /// Custom data added by [Config::stats_handler]
-    pub(crate) data: Option<String>,
+    pub(crate) data: Option<serde_json::Value>,
     /// Queue group to which this endpoint is assigned to.
     pub(crate) queue_group: String,
 }
@@ -173,7 +173,7 @@ pub struct Stats {
     #[serde(with = "serde_error_string")]
     pub last_error: Option<error::Error>,
     /// Custom data added by [crate::service::Config::stats_handler]
-    pub data: Option<String>,
+    pub data: Option<serde_json::Value>,
     /// Queue group to which this endpoint is assigned to.
     pub queue_group: String,
 }
diff --git a/async-nats/src/service/mod.rs b/async-nats/src/service/mod.rs
index a66456d0d..a938fde1d 100644
--- a/async-nats/src/service/mod.rs
+++ b/async-nats/src/service/mod.rs
@@ -163,7 +163,7 @@ impl ServiceBuilder {
     /// Handler for custom service statistics.
     pub fn stats_handler<F>(mut self, handler: F) -> Self
     where
-        F: FnMut(String, endpoint::Stats) -> String + Send + Sync + 'static,
+        F: FnMut(String, endpoint::Stats) -> serde_json::Value + Send + Sync + 'static,
     {
         self.stats_handler = Some(StatsHandler(Box::new(handler)));
         self
@@ -265,7 +265,7 @@ pub trait ServiceExt {
     /// let mut service = client
     ///     .service_builder()
     ///     .description("some service")
-    ///     .stats_handler(|endpoint, stats| format!("customstats"))
+    ///     .stats_handler(|endpoint, stats| serde_json::json!({ "endpoint": endpoint }))
     ///     .start("products", "1.0.0")
     ///     .await?;
     ///
@@ -870,7 +870,7 @@ impl EndpointBuilder {
     }
 }
 
-pub struct StatsHandler(pub Box<dyn FnMut(String, endpoint::Stats) -> String + Send>);
+pub struct StatsHandler(pub Box<dyn FnMut(String, endpoint::Stats) -> serde_json::Value + Send>);
 
 impl std::fmt::Debug for StatsHandler {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
diff --git a/async-nats/tests/service_tests.rs b/async-nats/tests/service_tests.rs
index 2cea4eb16..0c0999f54 100644
--- a/async-nats/tests/service_tests.rs
+++ b/async-nats/tests/service_tests.rs
@@ -517,7 +517,7 @@ mod service {
 
         let service = client
             .service_builder()
-            .stats_handler(|endpoint, _| format!("custom data for {endpoint}"))
+            .stats_handler(|endpoint, _| serde_json::json!({ "endpoint": endpoint }))
             .description("a cross service")
             .start("cross", "1.0.0")
             .await