diff --git a/TESTING.md b/TESTING.md
index 85baeac..d514756 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -155,6 +155,7 @@ Expected relay output:
 
 ```text
 lanparty-relay configured for 0.0.0.0:8443/udp ...
+lanparty-relay wrote development certificate to relay-cert.der
 lanparty-relay listening on 0.0.0.0:8443
 ```
 
diff --git a/crates/lanparty-relay/src/main.rs b/crates/lanparty-relay/src/main.rs
index 0150daf..f568e6d 100644
--- a/crates/lanparty-relay/src/main.rs
+++ b/crates/lanparty-relay/src/main.rs
@@ -14,6 +14,12 @@ async fn run(config: RelayConfig) -> anyhow::Result<()> {
         config.max_clients_per_room()
     );
     let server = RelayServer::bind(&config)?;
+    if let Some(path) = config.dev_cert_der_out() {
+        println!(
+            "lanparty-relay wrote development certificate to {}",
+            path.display()
+        );
+    }
     println!("lanparty-relay listening on {}", server.local_addr()?);
     server.run_until_shutdown().await
 }