diff --git a/frontend/src/components/ResponsePanel.tsx b/frontend/src/components/ResponsePanel.tsx
index ea0ad43..7cb6319 100644
--- a/frontend/src/components/ResponsePanel.tsx
+++ b/frontend/src/components/ResponsePanel.tsx
@@ -7,9 +7,10 @@ import { getPdfViewerUrl } from '../lib/api'
 import { processCitations, processCitationsForSubq, extractCitedSources, highlightTerms } from '../utils/citationParser'
 import { bulletizeMarkdown } from '../utils/citationParser'
 
+const V2_BASE = `${import.meta.env.VITE_API_BASE_URL ?? 'http://localhost:8000/api/v1'}/v2`
+
 function getHighlightUrl(document_id: string, chunk_index: number, sub_question: string): string {
-  const base = 'http://localhost:8000/api/v1/v2'
-  return `${base}/highlights?document_id=${encodeURIComponent(document_id)}&chunk_index=${chunk_index}&sub_question=${encodeURIComponent(sub_question)}`
+  return `${V2_BASE}/highlights?document_id=${encodeURIComponent(document_id)}&chunk_index=${chunk_index}&sub_question=${encodeURIComponent(sub_question)}`
 }
 
 interface ResponsePanelProps {
@@ -220,8 +221,8 @@ function SubQuestionSections({
     const startTime = performance.now()
     
     const url = historyId
-      ? `http://localhost:8000/api/v1/v2/highlights/batch?history_id=${historyId}`
-      : 'http://localhost:8000/api/v1/v2/highlights/batch'
+      ? `${V2_BASE}/highlights/batch?history_id=${historyId}`
+      : `${V2_BASE}/highlights/batch`
     fetch(url, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
diff --git a/frontend/src/utils/citationParser.ts b/frontend/src/utils/citationParser.ts
index abb78d1..b224bd6 100644
--- a/frontend/src/utils/citationParser.ts
+++ b/frontend/src/utils/citationParser.ts
@@ -61,8 +61,8 @@ export function processCitationsForSubq(
 
 function buildCitationUrl(source: SourceMetadata, highlightReady?: boolean): string | null {
   if (highlightReady && source.document_id && source.sub_question_text) {
-    const base = 'http://localhost:8000/api/v1/v2'
-    return `${base}/highlights?document_id=${encodeURIComponent(source.document_id)}&chunk_index=${source.chunk_index}&sub_question=${encodeURIComponent(source.sub_question_text)}`
+    const v2Base = `${import.meta.env.VITE_API_BASE_URL ?? 'http://localhost:8000/api/v1'}/v2`
+    return `${v2Base}/highlights?document_id=${encodeURIComponent(source.document_id)}&chunk_index=${source.chunk_index}&sub_question=${encodeURIComponent(source.sub_question_text)}`
   }
   if (source.chunk_file_path) {
     return getPdfViewerUrl(