diff --git a/kustomize/base/api/server.mjs b/kustomize/base/api/server.mjs
index a2e2547..00233fb 100644
--- a/kustomize/base/api/server.mjs
+++ b/kustomize/base/api/server.mjs
@@ -744,7 +744,7 @@ function computeCandleFlowMovesFromTicks({ candle, bucketSeconds, points, rows,
 }
 
 function parseTimeframeToSeconds(tf) {
-  const v = String(tf || '').trim().toLowerCase();
+  const v = normalizeChartTimeframe(tf);
   if (!v) return 60;
   const m = v.match(/^(\d+)(s|m|h|d)$/);
   if (!m) throw new Error(`invalid_tf`);
@@ -755,6 +755,40 @@ function parseTimeframeToSeconds(tf) {
   return num * mult;
 }
 
+const SUPPORTED_CHART_TIMEFRAMES = new Set([
+  '1s',
+  '5s',
+  '15s',
+  '30s',
+  '1m',
+  '5m',
+  '15m',
+  '30m',
+  '1h',
+  '4h',
+  '8h',
+  '12h',
+  '1d',
+]);
+
+function normalizeChartTimeframe(tf) {
+  const raw = String(tf || '').trim();
+  if (!raw) return '1m';
+
+  const aliased =
+    raw === '1D' || raw === '24h' || raw === '24H'
+      ? '1d'
+      : raw === '1H'
+        ? '1h'
+        : raw.toLowerCase();
+
+  if (!SUPPORTED_CHART_TIMEFRAMES.has(aliased)) {
+    throw new Error('invalid_tf');
+  }
+
+  return aliased;
+}
+
 function fillForwardCandles(candles, { bucketSeconds, limit, nowSec }) {
   if (!Array.isArray(candles) || candles.length === 0) return [];
   if (!Number.isFinite(bucketSeconds) || bucketSeconds <= 0) return candles;