diff --git a/ngrok/src/config/http.rs b/ngrok/src/config/http.rs
index a22a568..f55020b 100644
--- a/ngrok/src/config/http.rs
+++ b/ngrok/src/config/http.rs
@@ -167,7 +167,8 @@ impl TunnelConfig for HttpOptions {
     fn opts(&self) -> Option<BindOpts> {
         let http_endpoint = HttpEndpoint {
             proxy_proto: self.common_opts.proxy_proto,
-            hostname: self.domain.clone().unwrap_or_default(),
+            domain: self.domain.clone().unwrap_or_default(),
+            hostname: String::new(),
             compression: self.compression.then_some(Compression {}),
             circuit_breaker: (self.circuit_breaker != 0f64).then_some(CircuitBreaker {
                 error_threshold: self.circuit_breaker,
@@ -597,7 +598,7 @@ mod test {
         let opts = tunnel_cfg.opts().unwrap();
         assert!(matches!(opts, BindOpts::Http { .. }));
         if let BindOpts::Http(endpoint) = opts {
-            assert_eq!(DOMAIN, endpoint.hostname);
+            assert_eq!(DOMAIN, endpoint.domain);
             assert_eq!(String::default(), endpoint.subdomain);
             assert!(matches!(endpoint.proxy_proto, ProxyProto::V2));
 
@@ -715,4 +716,28 @@ mod test {
         builder.binding("public");
         builder.binding("internal");
     }
+
+    #[test]
+    fn test_binding_with_domain() {
+        let mut builder = HttpTunnelBuilder {
+            session: None,
+            options: Default::default(),
+        };
+        builder.binding("internal").domain("foo.internal");
+
+        // Check that both binding and domain are set
+        assert_eq!(vec!["internal"], builder.options.bindings);
+        assert_eq!(Some("foo.internal".to_string()), builder.options.domain);
+
+        // Check that they're properly included in extra() and opts()
+        let extra = builder.options.extra();
+        assert_eq!(vec!["internal"], extra.bindings);
+
+        let opts = builder.options.opts().unwrap();
+        if let BindOpts::Http(endpoint) = opts {
+            assert_eq!("foo.internal", endpoint.domain);
+        } else {
+            panic!("Expected Http endpoint");
+        }
+    }
 }
diff --git a/ngrok/src/config/tls.rs b/ngrok/src/config/tls.rs
index 72c32a7..e4133c8 100644
--- a/ngrok/src/config/tls.rs
+++ b/ngrok/src/config/tls.rs
@@ -76,8 +76,7 @@ impl TunnelConfig for TlsOptions {
         let mut tls_endpoint = proto::TlsEndpoint::default();
 
         if let Some(domain) = self.domain.as_ref() {
-            // note: hostname and subdomain are going away in favor of just domain
-            tls_endpoint.hostname = domain.clone();
+            tls_endpoint.domain = domain.clone();
         }
         tls_endpoint.proxy_proto = self.common_opts.proxy_proto;
 
@@ -318,7 +317,7 @@ mod test {
         let opts = tunnel_cfg.opts().unwrap();
         assert!(matches!(opts, BindOpts::Tls { .. }));
         if let BindOpts::Tls(endpoint) = opts {
-            assert_eq!(DOMAIN, endpoint.hostname);
+            assert_eq!(DOMAIN, endpoint.domain);
             assert_eq!(String::default(), endpoint.subdomain);
             assert!(matches!(endpoint.proxy_proto, ProxyProto::V2));
             assert!(!endpoint.mutual_tls_at_agent);
diff --git a/ngrok/src/internals/proto.rs b/ngrok/src/internals/proto.rs
index cdcb495..016f91b 100644
--- a/ngrok/src/internals/proto.rs
+++ b/ngrok/src/internals/proto.rs
@@ -672,6 +672,8 @@ impl From<String> for PolicyWrapper {
 #[derive(Serialize, Deserialize, Debug, Clone, Default)]
 #[serde(rename_all = "PascalCase")]
 pub struct HttpEndpoint {
+    #[serde(default)]
+    pub domain: String,
     pub hostname: String,
     pub auth: String,
     pub subdomain: String,
@@ -833,6 +835,8 @@ pub struct TcpEndpoint {
 #[derive(Serialize, Deserialize, Debug, Clone, Default)]
 #[serde(rename_all = "PascalCase")]
 pub struct TlsEndpoint {
+    #[serde(default)]
+    pub domain: String,
     pub hostname: String,
     pub subdomain: String,
     pub proxy_proto: ProxyProto,