diff --git a/frontend/src/components/MarketSearchPanel.tsx b/frontend/src/components/MarketSearchPanel.tsx
index b0098ee..7b310eb 100644
--- a/frontend/src/components/MarketSearchPanel.tsx
+++ b/frontend/src/components/MarketSearchPanel.tsx
@@ -5,6 +5,7 @@ import {
   toggleFavorite,
   FAVORITES_CHANGED_EVENT,
 } from '../utils/marketStorage';
+import { UPBIT_API } from '../utils/upbitApi';
 
 // ─── Types ───────────────────────────────────────────────────────────────────
 interface MarketInfo {
@@ -21,14 +22,21 @@ interface TickerInfo {
 }
 
 // ─── Constants ───────────────────────────────────────────────────────────────
-const UPBIT_API  = import.meta.env.DEV ? '/upbit-api/v1' : 'https://api.upbit.com/v1';
 const TICKER_TTL = 3000;   // 3초마다 시세 갱신
 
-function formatVol(vol: number): string {
-  if (vol >= 1e12) return `${(vol / 1e12).toFixed(1)}조`;
-  if (vol >= 1e8)  return `${(vol / 1e8).toFixed(0)}억`;
-  if (vol >= 1e4)  return `${(vol / 1e4).toFixed(0)}만`;
-  return vol.toLocaleString();
+function formatVol(vol: number | string | null | undefined): string {
+  const v = Number(vol);
+  if (!Number.isFinite(v)) return '-';
+  if (v >= 1e12) return `${(v / 1e12).toFixed(1)}조`;
+  if (v >= 1e8)  return `${(v / 1e8).toFixed(0)}억`;
+  if (v >= 1e4)  return `${(v / 1e4).toFixed(0)}만`;
+  return v.toLocaleString();
+}
+
+function formatChangeRate(raw: number | string | null | undefined): number | null {
+  const rate = Number(raw);
+  if (!Number.isFinite(rate)) return null;
+  return rate * 100;
 }
 
 // ─── Component ───────────────────────────────────────────────────────────────
@@ -86,7 +94,10 @@ export const MarketSearchPanel: React.FC<MarketSearchPanelProps> = ({
   useEffect(() => {
     setLoading(true);
     fetch(`${UPBIT_API}/market/all?isDetails=false`)
-      .then(r => r.json())
+      .then(r => {
+        if (!r.ok) throw new Error(`market/all ${r.status}`);
+        return r.json();
+      })
       .then((data: Array<{ market: string; korean_name: string; english_name: string }>) => {
         const krw = data
           .filter(m => m.market.startsWith('KRW-'))
@@ -129,9 +140,11 @@ export const MarketSearchPanel: React.FC<MarketSearchPanelProps> = ({
     for (let i = 0; i < allCodes.length; i += BATCH) {
       const batch = allCodes.slice(i, i + BATCH).join(',');
       try {
-        const data: Array<{ market: string } & TickerInfo> =
-          await fetch(`${UPBIT_API}/ticker?markets=${batch}`).then(r => r.json());
-        results.push(...data);
+        const res = await fetch(`${UPBIT_API}/ticker?markets=${batch}`);
+        if (!res.ok) continue;
+        const data: unknown = await res.json();
+        if (!Array.isArray(data)) continue;
+        results.push(...(data as Array<{ market: string } & TickerInfo>));
       } catch { /* ignore partial failures */ }
     }
 
@@ -328,7 +341,7 @@ export const MarketSearchPanel: React.FC<MarketSearchPanelProps> = ({
             const isFav     = favs.has(m.market);
             const isAdded   = addedMarkets?.has(m.market) ?? false;
             const isActive  = m.market === currentMarket;
-            const rate      = tk ? tk.signed_change_rate * 100 : null;
+            const rate      = tk ? formatChangeRate(tk.signed_change_rate) : null;
             const isUp      = rate !== null && rate >= 0;
 
             return (
@@ -373,7 +386,9 @@ export const MarketSearchPanel: React.FC<MarketSearchPanelProps> = ({
                 {!embedded && (
                   <>
                     <span className="msp-col msp-col-price">
-                      {tk ? tk.trade_price.toLocaleString() : '-'}
+                      {tk && Number.isFinite(Number(tk.trade_price))
+                        ? Number(tk.trade_price).toLocaleString()
+                        : '-'}
                     </span>
                     <span className={`msp-col msp-col-change ${rate === null ? '' : isUp ? 'up' : 'down'}`}>
                       {rate === null
diff --git a/frontend/src/hooks/useMarketTicker.ts b/frontend/src/hooks/useMarketTicker.ts
index 1d35ba5..7386af7 100644
--- a/frontend/src/hooks/useMarketTicker.ts
+++ b/frontend/src/hooks/useMarketTicker.ts
@@ -10,6 +10,7 @@
 
 import { useState, useEffect, useRef, useCallback } from 'react';
 import { setMarketNames } from '../utils/marketNameCache';
+import { UPBIT_API } from '../utils/upbitApi';
 
 export type ChangeDir = 'RISE' | 'FALL' | 'EVEN';
 
@@ -69,7 +70,7 @@ function getMarketCode(raw: UpbitTickerRaw): string {
 }
 
 async function fetchAllMarkets(): Promise<MarketInfo[]> {
-  const res = await fetch('/upbit-api/v1/market/all?isDetails=true');
+  const res = await fetch(`${UPBIT_API}/market/all?isDetails=true`);
   if (!res.ok) throw new Error(`market/all ${res.status}`);
   const data: UpbitMarketAll[] = await res.json();
   const krw = data.filter(m => m.market.startsWith('KRW-'));
@@ -88,7 +89,7 @@ async function fetchAllTickers(markets: string[]): Promise<UpbitTickerRaw[]> {
   for (let i = 0; i < markets.length; i += 100) {
     const chunk = markets.slice(i, i + 100);
     try {
-      const res = await fetch(`/upbit-api/v1/ticker?markets=${chunk.join(',')}`);
+      const res = await fetch(`${UPBIT_API}/ticker?markets=${chunk.join(',')}`);
       if (res.ok) results.push(...(await res.json()));
     } catch { /* 부분 실패 무시 */ }
   }
diff --git a/frontend/src/utils/upbitApi.ts b/frontend/src/utils/upbitApi.ts
index e77b1e7..01a678f 100644
--- a/frontend/src/utils/upbitApi.ts
+++ b/frontend/src/utils/upbitApi.ts
@@ -4,7 +4,8 @@ import type { OHLCVBar, Timeframe } from '../types';
 // 개발: Vite proxy (/upbit-api) → https://api.upbit.com
 // 프로덕션: nginx proxy (/upbit-api) → https://api.upbit.com
 // 항상 동일한 상대 경로를 사용하므로 CORS 없이 동일 오리진으로 요청됨
-const UPBIT_API = '/upbit-api/v1';
+/** dev: Vite proxy, prod: nginx proxy — 항상 동일 오리진 상대 경로 */
+export const UPBIT_API = '/upbit-api/v1';
 
 export const UPBIT_MARKETS = [
   'KRW-BTC', 'KRW-ETH', 'KRW-XRP', 'KRW-SOL', 'KRW-DOGE',