diff --git a/frontend/src/pages/TargetDetailPage.jsx b/frontend/src/pages/TargetDetailPage.jsx
index d33df01..f6f7983 100644
--- a/frontend/src/pages/TargetDetailPage.jsx
+++ b/frontend/src/pages/TargetDetailPage.jsx
@@ -36,6 +36,24 @@ function formatSeconds(value) {
   return `${(value / 3600).toFixed(1)}h`;
 }
 
+function formatNumber(value, digits = 2) {
+  if (value === null || value === undefined || Number.isNaN(Number(value))) return "-";
+  return Number(value).toFixed(digits);
+}
+
+function MetricsTooltip({ active, payload, label }) {
+  if (!active || !payload || payload.length === 0) return null;
+  const row = payload[0]?.payload || {};
+  return (
+    <div className="chart-tooltip">
+      <div className="chart-tooltip-time">{label}</div>
+      <div className="chart-tooltip-item c1">connections: {formatNumber(row.connections, 0)}</div>
+      <div className="chart-tooltip-item c2">tps: {formatNumber(row.tps, 2)}</div>
+      <div className="chart-tooltip-item c3">cache: {formatNumber(row.cache, 2)}%</div>
+    </div>
+  );
+}
+
 async function loadMetric(targetId, metric, range, tokens, refresh) {
   const { from, to } = toQueryRange(range);
   return apiFetch(
@@ -91,13 +109,29 @@ export function TargetDetailPage() {
   }, [id, range, tokens, refresh]);
 
   const chartData = useMemo(
-    () =>
-      (series.connections || []).map((point, idx) => ({
-        ts: new Date(point.ts).toLocaleTimeString(),
-        connections: point.value,
-        xacts: series.xacts?.[idx]?.value || 0,
-        cache: series.cache?.[idx]?.value || 0,
-      })),
+    () => {
+      const con = series.connections || [];
+      const xacts = series.xacts || [];
+      const cache = series.cache || [];
+      return con.map((point, idx) => {
+        const prev = xacts[idx - 1];
+        const curr = xacts[idx];
+        let tps = 0;
+        if (prev && curr) {
+          const dt = (new Date(curr.ts).getTime() - new Date(prev.ts).getTime()) / 1000;
+          const dx = (curr.value || 0) - (prev.value || 0);
+          if (dt > 0 && dx >= 0) {
+            tps = dx / dt;
+          }
+        }
+        return {
+          ts: new Date(point.ts).toLocaleTimeString(),
+          connections: point.value,
+          tps,
+          cache: (cache[idx]?.value || 0) * 100,
+        };
+      });
+    },
     [series]
   );
 
@@ -232,11 +266,12 @@ export function TargetDetailPage() {
         <ResponsiveContainer width="100%" height="85%">
           <LineChart data={chartData}>
             <XAxis dataKey="ts" hide />
-            <YAxis />
-            <Tooltip />
-            <Line type="monotone" dataKey="connections" stroke="#38bdf8" dot={false} />
-            <Line type="monotone" dataKey="xacts" stroke="#22c55e" dot={false} />
-            <Line type="monotone" dataKey="cache" stroke="#f59e0b" dot={false} />
+            <YAxis yAxisId="left" />
+            <YAxis yAxisId="right" orientation="right" domain={[0, 100]} />
+            <Tooltip content={<MetricsTooltip />} />
+            <Line yAxisId="left" type="monotone" dataKey="connections" stroke="#38bdf8" dot={false} strokeWidth={2} />
+            <Line yAxisId="left" type="monotone" dataKey="tps" stroke="#22c55e" dot={false} strokeWidth={2} />
+            <Line yAxisId="right" type="monotone" dataKey="cache" stroke="#f59e0b" dot={false} strokeWidth={2} />
           </LineChart>
         </ResponsiveContainer>
       </div>
diff --git a/frontend/src/styles.css b/frontend/src/styles.css
index 98ddcb0..6f2c718 100644
--- a/frontend/src/styles.css
+++ b/frontend/src/styles.css
@@ -359,6 +359,37 @@ td {
   margin: 8px 0 0 18px;
 }
 
+.chart-tooltip {
+  background: #0f1934ee;
+  border: 1px solid #2f4a8b;
+  border-radius: 10px;
+  padding: 10px 12px;
+  min-width: 170px;
+}
+
+.chart-tooltip-time {
+  font-size: 12px;
+  color: #9cb2d8;
+  margin-bottom: 6px;
+}
+
+.chart-tooltip-item {
+  font-size: 14px;
+  margin: 3px 0;
+}
+
+.chart-tooltip-item.c1 {
+  color: #38bdf8;
+}
+
+.chart-tooltip-item.c2 {
+  color: #22c55e;
+}
+
+.chart-tooltip-item.c3 {
+  color: #f59e0b;
+}
+
 @media (max-width: 980px) {
   body {
     overflow: auto;