diff --git a/frontend/src/api/endpoints.ts b/frontend/src/api/endpoints.ts
index 573b58a8..e0dc7742 100644
--- a/frontend/src/api/endpoints.ts
+++ b/frontend/src/api/endpoints.ts
@@ -77,6 +77,10 @@ const endpoints = {
     WORKFLOWS: '/api/workflows',
     WORKFLOW: (id: string) => `/api/workflows/${id}`,
   },
+  V1: {
+    CHAT_COMPLETIONS: '/v1/chat/completions',
+    MODELS: '/v1/models',
+  },
   CONVERSATION: {
     ANSWER: '/api/answer',
     ANSWER_STREAMING: '/stream',
diff --git a/frontend/src/api/services/conversationService.ts b/frontend/src/api/services/conversationService.ts
index 853a6863..a79370aa 100644
--- a/frontend/src/api/services/conversationService.ts
+++ b/frontend/src/api/services/conversationService.ts
@@ -54,6 +54,18 @@ const conversationService = {
     apiClient.get(endpoints.CONVERSATION.DELETE_ALL, token, {}),
   update: (data: any, token: string | null): Promise<any> =>
     apiClient.post(endpoints.CONVERSATION.UPDATE, data, token, {}),
+  chatCompletions: (
+    data: any,
+    agentApiKey: string,
+    signal: AbortSignal,
+  ): Promise<any> =>
+    apiClient.post(
+      endpoints.V1.CHAT_COMPLETIONS,
+      data,
+      null,
+      { Authorization: `Bearer ${agentApiKey}` },
+      signal,
+    ),
 };
 
 export default conversationService;
diff --git a/frontend/src/conversation/conversationHandlers.ts b/frontend/src/conversation/conversationHandlers.ts
index 9bed754f..c7fcdf44 100644
--- a/frontend/src/conversation/conversationHandlers.ts
+++ b/frontend/src/conversation/conversationHandlers.ts
@@ -254,6 +254,190 @@ export function handleSubmitToolActions(
   });
 }
 
+/**
+ * Stream a chat completion via the /v1/chat/completions endpoint.
+ *
+ * Translates the standard streaming format (choices[0].delta) back into
+ * the internal DocsGPT event shape so the existing Redux reducers can
+ * consume the events without any changes.
+ */
+export function handleV1ChatCompletionStreaming(
+  question: string,
+  signal: AbortSignal,
+  agentApiKey: string,
+  history: { prompt: string; response: string }[],
+  onEvent: (event: MessageEvent) => void,
+  tools?: any[],
+  attachments?: string[],
+): Promise<Answer> {
+  // Build messages array from history + current question
+  const messages: any[] = [];
+  for (const h of history) {
+    messages.push({ role: 'user', content: h.prompt });
+    messages.push({ role: 'assistant', content: h.response });
+  }
+  messages.push({ role: 'user', content: question });
+
+  const payload: any = {
+    messages,
+    stream: true,
+  };
+  if (tools && tools.length > 0) {
+    payload.tools = tools;
+  }
+  if (attachments && attachments.length > 0) {
+    payload.docsgpt = { attachments };
+  }
+
+  return new Promise<Answer>((resolve, reject) => {
+    conversationService
+      .chatCompletions(payload, agentApiKey, signal)
+      .then((response) => {
+        if (!response.body) throw Error('No response body');
+
+        let buffer = '';
+        const reader = response.body.getReader();
+        const decoder = new TextDecoder('utf-8');
+
+        const processStream = ({
+          done,
+          value,
+        }: ReadableStreamReadResult<Uint8Array>) => {
+          if (done) return;
+
+          const chunk = decoder.decode(value);
+          buffer += chunk;
+
+          const events = buffer.split('\n\n');
+          buffer = events.pop() ?? '';
+
+          for (const event of events) {
+            if (!event.trim().startsWith('data:')) continue;
+
+            const dataLine = event
+              .split('\n')
+              .map((line: string) => line.replace(/^data:\s?/, ''))
+              .join('');
+
+            const trimmed = dataLine.trim();
+
+            // Handle [DONE] sentinel
+            if (trimmed === '[DONE]') {
+              onEvent(
+                new MessageEvent('message', {
+                  data: JSON.stringify({ type: 'end' }),
+                }),
+              );
+              continue;
+            }
+
+            try {
+              const parsed = JSON.parse(trimmed);
+              // Translate standard format to DocsGPT internal events
+              const translated = translateV1ChunkToInternalEvents(parsed);
+              for (const evt of translated) {
+                onEvent(
+                  new MessageEvent('message', {
+                    data: JSON.stringify(evt),
+                  }),
+                );
+              }
+            } catch {
+              // Skip unparseable chunks
+            }
+          }
+
+          reader.read().then(processStream).catch(reject);
+        };
+
+        reader.read().then(processStream).catch(reject);
+      })
+      .catch((error) => {
+        console.error('V1 chat completion stream failed:', error);
+        reject(error);
+      });
+  });
+}
+
+/**
+ * Translate a single v1 streaming chunk to internal DocsGPT event(s).
+ *
+ * Standard format: {"choices": [{"delta": {"content": "chunk"}, ...}]}
+ * Extension format: {"docsgpt": {"type": "source", ...}}
+ */
+function translateV1ChunkToInternalEvents(
+  chunk: any,
+): { type: string; [key: string]: any }[] {
+  const events: { type: string; [key: string]: any }[] = [];
+
+  // DocsGPT extension chunks
+  if (chunk.docsgpt) {
+    const ext = chunk.docsgpt;
+    if (ext.type === 'source') {
+      events.push({ type: 'source', source: ext.sources });
+    } else if (ext.type === 'tool_call') {
+      events.push({ type: 'tool_call', data: ext.data });
+    } else if (ext.type === 'tool_calls_pending') {
+      events.push({
+        type: 'tool_calls_pending',
+        data: { pending_tool_calls: ext.pending_tool_calls },
+      });
+    } else if (ext.type === 'id') {
+      events.push({ type: 'id', id: ext.conversation_id });
+    }
+    return events;
+  }
+
+  // Error chunks
+  if (chunk.error) {
+    events.push({ type: 'error', error: chunk.error.message || 'Error' });
+    return events;
+  }
+
+  // Standard choices chunks
+  const choice = chunk.choices?.[0];
+  if (!choice) return events;
+
+  const delta = choice.delta || {};
+  const finishReason = choice.finish_reason;
+
+  if (delta.content) {
+    events.push({ type: 'answer', answer: delta.content });
+  }
+
+  if (delta.reasoning_content) {
+    events.push({ type: 'thought', thought: delta.reasoning_content });
+  }
+
+  if (delta.tool_calls) {
+    for (const tc of delta.tool_calls) {
+      events.push({
+        type: 'tool_call',
+        data: {
+          call_id: tc.id,
+          action_name: tc.function?.name || '',
+          tool_name: tc.function?.name || '',
+          arguments: tc.function?.arguments
+            ? JSON.parse(tc.function.arguments)
+            : {},
+          status: 'requires_client_execution',
+        },
+      });
+    }
+  }
+
+  if (finishReason === 'stop') {
+    events.push({ type: 'end' });
+  } else if (finishReason === 'tool_calls') {
+    events.push({
+      type: 'tool_calls_pending',
+      data: { pending_tool_calls: [] },
+    });
+  }
+
+  return events;
+}
+
 export function handleSearch(
   question: string,
   token: string | null,
diff --git a/frontend/src/conversation/conversationSlice.ts b/frontend/src/conversation/conversationSlice.ts
index 76f3beb7..6181e1da 100644
--- a/frontend/src/conversation/conversationSlice.ts
+++ b/frontend/src/conversation/conversationSlice.ts
@@ -11,6 +11,7 @@ import {
   handleFetchAnswer,
   handleFetchAnswerSteaming,
   handleSubmitToolActions,
+  handleV1ChatCompletionStreaming,
 } from './conversationHandlers';
 import {
   Answer,
@@ -28,6 +29,7 @@ const initialState: ConversationState = {
 };
 
 const API_STREAMING = import.meta.env.VITE_API_STREAMING === 'true';
+const USE_V1_API = import.meta.env.VITE_USE_V1_API === 'true';
 
 let abortController: AbortController | null = null;
 export function handleAbort() {
@@ -61,7 +63,102 @@ export const fetchAnswer = createAsyncThunk<
     state.preference.selectedModel?.id;
 
   if (state.preference) {
-    if (API_STREAMING) {
+    const agentKey = state.preference.selectedAgent?.key;
+    if (USE_V1_API && agentKey) {
+      // Build history from prior queries for v1 format
+      const v1History = state.conversation.queries
+        .filter((q) => q.response)
+        .map((q) => ({ prompt: q.prompt, response: q.response || '' }));
+
+      await handleV1ChatCompletionStreaming(
+        question,
+        signal,
+        agentKey,
+        v1History,
+        (event) => {
+          const data = JSON.parse(event.data);
+          const targetIndex = indx ?? state.conversation.queries.length - 1;
+
+          if (currentConversationId === state.conversation.conversationId) {
+            if (data.type === 'end') {
+              dispatch(conversationSlice.actions.setStatus('idle'));
+              getConversations(state.preference.token)
+                .then((fetchedConversations) => {
+                  dispatch(setConversations(fetchedConversations));
+                })
+                .catch((error) => {
+                  console.error('Failed to fetch conversations: ', error);
+                });
+              if (!isSourceUpdated) {
+                dispatch(
+                  updateStreamingSource({
+                    conversationId: currentConversationId,
+                    index: targetIndex,
+                    query: { sources: [] },
+                  }),
+                );
+              }
+            } else if (data.type === 'id') {
+              const currentState = getState() as RootState;
+              if (currentState.conversation.conversationId === null) {
+                dispatch(
+                  updateConversationId({
+                    query: { conversationId: data.id },
+                  }),
+                );
+              }
+            } else if (data.type === 'thought') {
+              dispatch(
+                updateThought({
+                  conversationId: currentConversationId,
+                  index: targetIndex,
+                  query: { thought: data.thought },
+                }),
+              );
+            } else if (data.type === 'source') {
+              isSourceUpdated = true;
+              dispatch(
+                updateStreamingSource({
+                  conversationId: currentConversationId,
+                  index: targetIndex,
+                  query: { sources: data.source ?? [] },
+                }),
+              );
+            } else if (data.type === 'tool_call') {
+              dispatch(
+                updateToolCall({
+                  index: targetIndex,
+                  tool_call: data.data as ToolCallsType,
+                }),
+              );
+            } else if (data.type === 'tool_calls_pending') {
+              dispatch(
+                conversationSlice.actions.setStatus('awaiting_tool_actions'),
+              );
+            } else if (data.type === 'error') {
+              dispatch(conversationSlice.actions.setStatus('failed'));
+              dispatch(
+                conversationSlice.actions.raiseError({
+                  conversationId: currentConversationId,
+                  index: targetIndex,
+                  message: data.error,
+                }),
+              );
+            } else {
+              dispatch(
+                updateStreamingQuery({
+                  conversationId: currentConversationId,
+                  index: targetIndex,
+                  query: { response: data.answer },
+                }),
+              );
+            }
+          }
+        },
+        undefined,
+        attachmentIds.length > 0 ? attachmentIds : undefined,
+      );
+    } else if (API_STREAMING) {
       await handleFetchAnswerSteaming(
         question,
         signal,