diff --git a/config.yaml b/config.yaml
index 4a5f2bd..e66b6dd 100644
--- a/config.yaml
+++ b/config.yaml
@@ -10,6 +10,8 @@ providers:
 - name: volcengine
   api: https://ark.cn-beijing.volces.com/api/coding/v3/chat/completions
   transport: http
+  source_format: openai_chat
+  target_format: openai_chat
   verify_ssl: false
   model_list:
   - kimi-k2.5
diff --git a/src/presentation/templates/providers.html b/src/presentation/templates/providers.html
index e163d26..eeac1b1 100644
--- a/src/presentation/templates/providers.html
+++ b/src/presentation/templates/providers.html
@@ -477,6 +477,7 @@
         let activeProviderHelpTrigger = null;
         let activeProviderTab = 'providers';
         let authEntryCardSequence = 0;
+        let providerTransportAutoSyncEnabled = true;
         const providerHelpTopics = {
             transport: {
                 title: '上游传输怎么选',
@@ -1304,17 +1305,54 @@
             setSelectValueOrFallback('providerVerifySsl', provider?.verify_ssl === true ? 'true' : 'false', 'false');
             document.getElementById('providerModelList').value = Array.isArray(provider?.model_list) ? buildModelListValue(provider.model_list) : '';
             document.getElementById('providerHook').value = provider?.hook || '';
+            resetProviderTransportAutoSync(provider);
             updateProviderAuthModeFields();
             updateModelListCount();
             updateFetchModelsButtonState();
         }
 
-        function inferTransportFromApi(apiValue) {
+        function inferExplicitTransportFromApi(apiValue) {
             const normalized = String(apiValue ?? '').trim().toLowerCase();
             if (normalized.startsWith('ws://') || normalized.startsWith('wss://')) {
                 return 'websocket';
             }
-            return 'http';
+            if (normalized.startsWith('http://') || normalized.startsWith('https://')) {
+                return 'http';
+            }
+            return null;
+        }
+
+        function inferTransportFromApi(apiValue) {
+            return inferExplicitTransportFromApi(apiValue) || 'http';
+        }
+
+        function resetProviderTransportAutoSync(provider) {
+            const explicitTransport = inferExplicitTransportFromApi(provider?.api || '');
+            if (!provider) {
+                providerTransportAutoSyncEnabled = true;
+                return;
+            }
+            providerTransportAutoSyncEnabled = !explicitTransport || provider?.transport === explicitTransport;
+        }
+
+        function syncProviderTransportWithApi(force = false) {
+            const explicitTransport = inferExplicitTransportFromApi(document.getElementById('providerApi')?.value || '');
+            if (!explicitTransport || (!force && !providerTransportAutoSyncEnabled)) {
+                return;
+            }
+            setSelectValueOrFallback('providerTransport', explicitTransport, explicitTransport);
+        }
+
+        function handleProviderApiInput() {
+            syncProviderTransportWithApi();
+            updateFetchModelsButtonState();
+        }
+
+        function handleProviderTransportChange() {
+            const explicitTransport = inferExplicitTransportFromApi(document.getElementById('providerApi')?.value || '');
+            const selectedTransport = document.getElementById('providerTransport')?.value || '';
+            providerTransportAutoSyncEnabled = !explicitTransport || selectedTransport === explicitTransport;
+            updateFetchModelsButtonState();
         }
 
         function getEffectiveTransport() {
@@ -2599,9 +2637,9 @@
                 document.getElementById('modelDetailList').innerHTML = '';
             });
             document.getElementById('providerName').addEventListener('input', updateFetchModelsButtonState);
-            document.getElementById('providerApi').addEventListener('input', updateFetchModelsButtonState);
+            document.getElementById('providerApi').addEventListener('input', handleProviderApiInput);
             document.getElementById('providerAuthMode').addEventListener('change', updateFetchModelsButtonState);
-            document.getElementById('providerTransport').addEventListener('change', updateFetchModelsButtonState);
+            document.getElementById('providerTransport').addEventListener('change', handleProviderTransportChange);
             document.getElementById('providerModelList').addEventListener('input', updateModelListCount);
             document.getElementById('fetchModelSearchInput').addEventListener('input', renderFetchModelPicker);
             document.getElementById('modelSearchInput').addEventListener('input', renderModelDetailList);
diff --git a/tests/test_proxy_transport.py b/tests/test_proxy_transport.py
index e53d117..0945281 100644
--- a/tests/test_proxy_transport.py
+++ b/tests/test_proxy_transport.py
@@ -265,6 +265,10 @@ class ProviderTemplateTransportTests(unittest.TestCase):
         self.assertIn('id="providerTargetFormat"', html)
         self.assertIn('id="providerAuthMode"', html)
         self.assertIn('id="providerAuthGroup"', html)
+        self.assertIn('providerTransportAutoSyncEnabled', html)
+        self.assertIn('syncProviderTransportWithApi', html)
+        self.assertIn("document.getElementById('providerApi').addEventListener('input', handleProviderApiInput);", html)
+        self.assertIn("document.getElementById('providerTransport').addEventListener('change', handleProviderTransportChange);", html)
         self.assertIn('id="authGroupsContainer"', html)
         self.assertIn('id="authGroupModal"', html)
         self.assertIn('id="authEntryImportModal"', html)