diff --git a/apps/web/src/__tests__/api.test.tsx b/apps/web/src/__tests__/api.test.tsx
new file mode 100644
index 0000000..b480c3d
--- /dev/null
+++ b/apps/web/src/__tests__/api.test.tsx
@@ -0,0 +1,128 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const mockFrom = vi.fn();
+const mockSelect = vi.fn(() => ({ from: mockFrom }));
+
+const mockReturning = vi.fn();
+const mockValues = vi.fn(() => ({ returning: mockReturning }));
+const mockInsert = vi.fn(() => ({ values: mockValues }));
+
+const mockWhere = vi.fn();
+const mockDelete = vi.fn(() => ({ where: mockWhere }));
+
+vi.mock("../db", () => ({
+	getDb: () => ({
+		select: mockSelect,
+		insert: mockInsert,
+		delete: mockDelete,
+	}),
+}));
+
+import app from "../routes/api";
+
+describe("GET /examples", () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	it("returns 200 with HTML containing example items", async () => {
+		mockFrom.mockResolvedValueOnce([
+			{ id: "uuid-1", title: "Test Item 1", createdAt: new Date() },
+			{ id: "uuid-2", title: "Test Item 2", createdAt: new Date() },
+		]);
+
+		const res = await app.request("/examples");
+
+		expect(res.status).toBe(200);
+		const html = await res.text();
+		expect(html).toContain("Test Item 1");
+		expect(html).toContain("Test Item 2");
+	});
+
+	it("returns 200 with empty content when no examples exist", async () => {
+		mockFrom.mockResolvedValueOnce([]);
+
+		const res = await app.request("/examples");
+
+		expect(res.status).toBe(200);
+	});
+});
+
+describe("POST /examples", () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	it("returns 200 with HTML partial on valid input", async () => {
+		mockReturning.mockResolvedValueOnce([
+			{ id: "uuid-new", title: "New Item", createdAt: new Date() },
+		]);
+
+		const res = await app.request("/examples", {
+			method: "POST",
+			headers: { "Content-Type": "application/x-www-form-urlencoded" },
+			body: "title=New+Item",
+		});
+
+		expect(res.status).toBe(200);
+		const html = await res.text();
+		expect(html).toContain("New Item");
+		expect(mockInsert).toHaveBeenCalled();
+	});
+
+	it("returns 400 when title is empty", async () => {
+		const res = await app.request("/examples", {
+			method: "POST",
+			headers: { "Content-Type": "application/x-www-form-urlencoded" },
+			body: "title=",
+		});
+
+		expect(res.status).toBe(400);
+		const text = await res.text();
+		expect(text).toBe("Invalid input");
+		expect(mockInsert).not.toHaveBeenCalled();
+	});
+
+	it("returns 400 when title field is missing", async () => {
+		const res = await app.request("/examples", {
+			method: "POST",
+			headers: { "Content-Type": "application/x-www-form-urlencoded" },
+			body: "",
+		});
+
+		expect(res.status).toBe(400);
+		expect(mockInsert).not.toHaveBeenCalled();
+	});
+
+	it("returns 500 when database returns no rows", async () => {
+		mockReturning.mockResolvedValueOnce([]);
+
+		const res = await app.request("/examples", {
+			method: "POST",
+			headers: { "Content-Type": "application/x-www-form-urlencoded" },
+			body: "title=Something",
+		});
+
+		expect(res.status).toBe(500);
+		const text = await res.text();
+		expect(text).toBe("Failed to create");
+	});
+});
+
+describe("DELETE /examples/:id", () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	it("returns 200 on successful delete", async () => {
+		mockWhere.mockResolvedValueOnce(undefined);
+
+		const res = await app.request("/examples/some-uuid-123", {
+			method: "DELETE",
+		});
+
+		expect(res.status).toBe(200);
+		expect(mockDelete).toHaveBeenCalled();
+		expect(mockWhere).toHaveBeenCalled();
+	});
+});
diff --git a/apps/web/src/__tests__/app.test.ts b/apps/web/src/__tests__/app.test.ts
deleted file mode 100644
index 8954ceb..0000000
--- a/apps/web/src/__tests__/app.test.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import { describe, expect, it } from "vitest";
-
-describe("app", () => {
-	it("works", () => {
-		expect(true).toBe(true);
-	});
-});
diff --git a/docs/plan/0002-api-tests.md b/docs/plan/0002-api-tests.md
new file mode 100644
index 0000000..1ef2a5e
--- /dev/null
+++ b/docs/plan/0002-api-tests.md
@@ -0,0 +1,23 @@
+# 0002: APIルートのテスト追加
+
+## 目的
+
+placeholderテストを実際のAPIルートテストに置き換え、スターターテンプレートの品質を担保する。
+
+## 方針
+
+- Honoの `app.request()` でHTTPリクエストをシミュレート（サーバー起動不要）
+- `vi.mock` で `getDb()` をモックし、DB接続なしでテスト実行
+- Drizzleのチェーンパターンをモックで再現
+
+## テストケース
+
+| エンドポイント | ケース | 期待 |
+|--------------|--------|------|
+| GET /examples | アイテムあり | 200 + HTML |
+| GET /examples | アイテムなし | 200 |
+| POST /examples | 有効な入力 | 200 + HTML partial |
+| POST /examples | タイトル空 | 400 |
+| POST /examples | タイトルなし | 400 |
+| POST /examples | DB挿入失敗 | 500 |
+| DELETE /examples/:id | 正常削除 | 200 |