diff --git a/src/app/api/local-coding/sync/route.ts b/src/app/api/local-coding/sync/route.ts
index 6b444d7f4..38aa87b39 100644
--- a/src/app/api/local-coding/sync/route.ts
+++ b/src/app/api/local-coding/sync/route.ts
@@ -205,7 +205,7 @@ export async function POST(req: NextRequest) {
     );
   }
 
-  const incomingDates = [...new Set(newSessions.map((session) => session.date))];
+  const incomingDates = [...new Set((newSessions ?? []).map((session) => session.date))];
   const { data: existingSessionsForDates } = await supabaseAdmin
     .from("local_coding_sessions")
     .select("date")
@@ -278,7 +278,7 @@ export async function GET(req: NextRequest) {
   }
 
   const { searchParams } = new URL(req.url);
-  const rawDays = parseInt(searchParams.get("days") || "30", 10);
+  const rawDays = parseInt(searchParams.get("days", 10) || "30", 10);
   const days = validateDays(isNaN(rawDays) ? DEFAULT_DAYS : rawDays);
   const fromDate = new Date();
   fromDate.setDate(fromDate.getDate() - days);
diff --git a/src/app/api/metrics/languages/route.ts b/src/app/api/metrics/languages/route.ts
index ed24444af..675493f48 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`,
@@ -65,7 +65,7 @@ export async function GET(req: NextRequest) {
       if (!searchRes.ok) throw new Error("API Error");
 
       const raw = await searchRes.json();
-      const repoNames = Array.from(new Set<string>(raw.items.map((i: any) => i.repository.full_name)));
+      const repoNames = Array.from(new Set<string>(raw.(items ?? []).map((i: any) => i.repository.full_name)));
       const topRepoNames = repoNames.slice(0, 20);
       const langTotals: Record<string, number> = {};
       const failedRepos: Array<{ name: string; statusCode?: number; error: string }> = [];
diff --git a/src/app/api/metrics/repo-health/route.ts b/src/app/api/metrics/repo-health/route.ts
index 8e059da02..058acefe7 100644
--- a/src/app/api/metrics/repo-health/route.ts
+++ b/src/app/api/metrics/repo-health/route.ts
@@ -150,7 +150,7 @@ export async function GET(req: NextRequest) {
     return Response.json({ error: "Unauthorized" }, { status: 401 });
   }
 
-  const requestedDays = parseInt(req.nextUrl.searchParams.get("days") ?? "30", 10);
+  const requestedDays = parseInt(req.nextUrl.searchParams.get("days", 10) ?? "30", 10);
   // Only allow 7, 30, or 90 day windows — other values default to 30.
   const days = requestedDays === 7 || requestedDays === 30 || requestedDays === 90 ? requestedDays : 30;
 
diff --git a/src/components/ContributionHeatmap.tsx b/src/components/ContributionHeatmap.tsx
index 740750c0a..59028ff79 100644
--- a/src/components/ContributionHeatmap.tsx
+++ b/src/components/ContributionHeatmap.tsx
@@ -318,7 +318,7 @@ export default function ContributionHeatmap({
     commits.forEach((c) => {
       if (c.repo) reposSet.add(c.repo);
     });
-    return Array.from(reposSet).sort();
+    return Array.from(reposSet).sort((a, b) => a - b);
   }, [commits]);
 
   // Extract unique languages
@@ -329,7 +329,7 @@ export default function ContributionHeatmap({
         if (l.name) langsSet.add(l.name);
       });
     });
-    return Array.from(langsSet).sort();
+    return Array.from(langsSet).sort((a, b) => a - b);
   }, [reposData]);
 
   // Map each repo to its languages for quick lookup
@@ -379,7 +379,7 @@ export default function ContributionHeatmap({
   );
   const weekCount = Math.ceil(cells.length / 7);
   const maxCommits = Math.max(
-    ...cells.map((cell) => cell.count),
+    ...(cells ?? []).map((cell) => cell.count),
     1
   );
   // 100% MATHEMATICALLY PRECISE MONTH TRACKING SYSTEM
diff --git a/src/hooks/useRealtimeSync.ts b/src/hooks/useRealtimeSync.ts
index 0f43efa36..fe9689c64 100644
--- a/src/hooks/useRealtimeSync.ts
+++ b/src/hooks/useRealtimeSync.ts
@@ -97,7 +97,7 @@ export function useRealtimeSync(
 
     // Stabilise `events` so an inline array definition (e.g. `["INSERT", "DELETE"]`)
     // doesn't cause the effect to re-run on every render.
-    const eventsKey = [...events].sort().join(",");
+    const eventsKey = [...events].sort((a, b) => a - b).join(",");
 
     useEffect(() => {
         const supabase = getSupabaseClient();