diff --git a/codex-rs/codex-api/src/endpoint/responses_websocket.rs b/codex-rs/codex-api/src/endpoint/responses_websocket.rs
index d65caad86..50b3f40c5 100644
--- a/codex-rs/codex-api/src/endpoint/responses_websocket.rs
+++ b/codex-rs/codex-api/src/endpoint/responses_websocket.rs
@@ -113,7 +113,9 @@ impl<A: AuthProvider> ResponsesWebsocketClient<A> {
         extra_headers: HeaderMap,
         turn_state: Option<Arc<OnceLock<String>>>,
     ) -> Result<ResponsesWebsocketConnection, ApiError> {
-        let ws_url = Url::parse(&self.provider.url_for_path("responses"))
+        let ws_url = self
+            .provider
+            .websocket_url_for_path("responses")
             .map_err(|err| ApiError::Stream(format!("failed to build websocket URL: {err}")))?;
 
         let mut headers = self.provider.headers.clone();
diff --git a/codex-rs/codex-api/src/provider.rs b/codex-rs/codex-api/src/provider.rs
index 846a25bf5..8fba2905b 100644
--- a/codex-rs/codex-api/src/provider.rs
+++ b/codex-rs/codex-api/src/provider.rs
@@ -6,6 +6,7 @@ use http::Method;
 use http::header::HeaderMap;
 use std::collections::HashMap;
 use std::time::Duration;
+use url::Url;
 
 /// Wire-level APIs supported by a `Provider`.
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -105,6 +106,19 @@ impl Provider {
         self.base_url.to_ascii_lowercase().contains("openai.azure.")
             || matches_azure_responses_base_url(&self.base_url)
     }
+
+    pub fn websocket_url_for_path(&self, path: &str) -> Result<Url, url::ParseError> {
+        let mut url = Url::parse(&self.url_for_path(path))?;
+
+        let scheme = match url.scheme() {
+            "http" => "ws",
+            "https" => "wss",
+            "ws" | "wss" => return Ok(url),
+            _ => return Ok(url),
+        };
+        let _ = url.set_scheme(scheme);
+        Ok(url)
+    }
 }
 
 fn matches_azure_responses_base_url(base_url: &str) -> bool {
diff --git a/codex-rs/core/config.schema.json b/codex-rs/core/config.schema.json
index 596fe6d2f..aea80a91d 100644
--- a/codex-rs/core/config.schema.json
+++ b/codex-rs/core/config.schema.json
@@ -109,6 +109,9 @@
         "remote_models": {
           "type": "boolean"
         },
+        "responses_websockets": {
+          "type": "boolean"
+        },
         "shell_snapshot": {
           "type": "boolean"
         },
@@ -601,6 +604,9 @@
             "remote_models": {
               "type": "boolean"
             },
+            "responses_websockets": {
+              "type": "boolean"
+            },
             "shell_snapshot": {
               "type": "boolean"
             },
diff --git a/codex-rs/core/src/config/mod.rs b/codex-rs/core/src/config/mod.rs
index 934c54263..b65a20b79 100644
--- a/codex-rs/core/src/config/mod.rs
+++ b/codex-rs/core/src/config/mod.rs
@@ -1363,6 +1363,12 @@ impl Config {
             || cfg.sandbox_mode.is_some();
 
         let mut model_providers = built_in_model_providers();
+        if features.enabled(Feature::ResponsesWebsockets)
+            && let Some(provider) = model_providers.get_mut("openai")
+            && provider.is_openai()
+        {
+            provider.wire_api = crate::model_provider_info::WireApi::ResponsesWebsocket;
+        }
         // Merge user-defined providers into the built-in list.
         for (key, provider) in cfg.model_providers.into_iter() {
             model_providers.entry(key).or_insert(provider);
@@ -2511,6 +2517,30 @@ profile = "project"
         Ok(())
     }
 
+    #[test]
+    fn responses_websockets_feature_updates_openai_provider() -> std::io::Result<()> {
+        let codex_home = TempDir::new()?;
+        let mut entries = BTreeMap::new();
+        entries.insert("responses_websockets".to_string(), true);
+        let cfg = ConfigToml {
+            features: Some(crate::features::FeaturesToml { entries }),
+            ..Default::default()
+        };
+
+        let config = Config::load_from_base_config_with_overrides(
+            cfg,
+            ConfigOverrides::default(),
+            codex_home.path().to_path_buf(),
+        )?;
+
+        assert_eq!(
+            config.model_provider.wire_api,
+            crate::model_provider_info::WireApi::ResponsesWebsocket
+        );
+
+        Ok(())
+    }
+
     #[test]
     fn config_honors_explicit_file_oauth_store_mode() -> std::io::Result<()> {
         let codex_home = TempDir::new()?;
diff --git a/codex-rs/core/src/features.rs b/codex-rs/core/src/features.rs
index 94610f0b7..6d1c40769 100644
--- a/codex-rs/core/src/features.rs
+++ b/codex-rs/core/src/features.rs
@@ -107,6 +107,8 @@ pub enum Feature {
     Steer,
     /// Enable collaboration modes (Plan, Pair Programming, Execute).
     CollaborationModes,
+    /// Use the Responses API WebSocket transport for OpenAI by default.
+    ResponsesWebsockets,
 }
 
 impl Feature {
@@ -461,4 +463,10 @@ pub const FEATURES: &[FeatureSpec] = &[
         stage: Stage::Beta,
         default_enabled: false,
     },
+    FeatureSpec {
+        id: Feature::ResponsesWebsockets,
+        key: "responses_websockets",
+        stage: Stage::Beta,
+        default_enabled: false,
+    },
 ];