diff --git a/src/modules/mileage/api.ts b/src/modules/mileage/api.ts
new file mode 100644
index 0000000..986c433
--- /dev/null
+++ b/src/modules/mileage/api.ts
@@ -0,0 +1,28 @@
+import type { MonitoringData, TargetSummary, TargetVehicle, TrendPoint } from './types';
+
+const BASE = '/api/mileage';
+
+async function fetchJson<T>(url: string): Promise<T> {
+  const res = await fetch(url);
+  if (!res.ok) throw new Error(`API error: ${res.status} ${res.statusText}`);
+  return res.json();
+}
+
+export async function fetchMonitoring(): Promise<MonitoringData> {
+  return fetchJson<MonitoringData>(`${BASE}/monitoring`);
+}
+
+export async function fetchTargets(): Promise<TargetSummary[]> {
+  return fetchJson<TargetSummary[]>(`${BASE}/targets`);
+}
+
+export async function fetchTargetVehicles(targetId: number): Promise<TargetVehicle[]> {
+  return fetchJson<TargetVehicle[]>(`${BASE}/target/${targetId}/vehicles`);
+}
+
+export async function fetchTrend(targetId?: number, days = 7): Promise<TrendPoint[]> {
+  const params = new URLSearchParams();
+  if (targetId) params.set('targetId', String(targetId));
+  params.set('days', String(days));
+  return fetchJson<TrendPoint[]>(`${BASE}/trend?${params.toString()}`);
+}