diff --git a/src/app/api/metrics/languages/route.ts b/src/app/api/metrics/languages/route.ts
index ed24444af..010034e46 100644
--- a/src/app/api/metrics/languages/route.ts
+++ b/src/app/api/metrics/languages/route.ts
@@ -56,7 +56,7 @@ export async function GET(req: NextRequest) {
     const data = await withMetricsCache({ bypass, key, ttlSeconds: METRICS_CACHE_TTL_SECONDS.languages }, async () => {
       const headers = { Authorization: `Bearer ${token}`, Accept: "application/vnd.github+json" };
       const since = new Date();
-      const rawDays = parseInt(req.nextUrl.searchParams.get("days") ?? "90", 10);    const days = Number.isFinite(rawDays) && rawDays > 0 ? Math.min(rawDays, 365) : 90;
+      const rawDays = parseInt(req.nextUrl.searchParams.get("days", 10) ?? "90", 10);    const days = Number.isFinite(rawDays) && rawDays > 0 ? Math.min(rawDays, 365) : 90;
 
       const searchRes = await fetch(
         `${GITHUB_API}/search/commits?q=author:${githubLogin}+author-date:>=${since.toISOString().slice(0, 10)}&per_page=100&sort=author-date&order=desc`,
diff --git a/src/app/api/metrics/productive-hours/route.ts b/src/app/api/metrics/productive-hours/route.ts
index 5bb62d383..839a900c4 100644
--- a/src/app/api/metrics/productive-hours/route.ts
+++ b/src/app/api/metrics/productive-hours/route.ts
@@ -223,7 +223,7 @@ export async function GET(req: NextRequest) {
   } else {
     const daysParam = searchParams.get("days");
     const parsedDays = daysParam ? parseInt(daysParam, 10) : NaN;
-    days = isNaN(parsedDays) ? 90 : Math.max(1, Math.min(365, parsedDays));
+    days = Number.isNaN(parsedDays) ? 90 : Math.max(1, Math.min(365, parsedDays));
   }
 
   const accountId = searchParams.get("accountId");
diff --git a/src/app/api/milestones/route.ts b/src/app/api/milestones/route.ts
index 4019a3d7f..19ec9c30c 100644
--- a/src/app/api/milestones/route.ts
+++ b/src/app/api/milestones/route.ts
@@ -92,7 +92,7 @@ export async function POST(req: Request) {
       ? unit.trim().slice(0, MAX_UNIT_LEN)
       : "units";
 
-  if (typeof targetDate !== "string" || isNaN(new Date(targetDate).getTime())) {
+  if (typeof targetDate !== "string" || Number.isNaN(new Date(targetDate).getTime())) {
     return NextResponse.json({ error: "targetDate must be a valid date string" }, { status: 400 });
   }