diff --git a/web/package-lock.json b/web/package-lock.json
index 8bfb5cd..2a4180e 100644
--- a/web/package-lock.json
+++ b/web/package-lock.json
@@ -8,7 +8,6 @@
       "name": "web",
       "version": "0.1.0",
       "dependencies": {
-        "@types/react-router-dom": "^5.3.3",
         "react": "^19.2.4",
         "react-dom": "^19.2.4",
         "react-router-dom": "^7.13.1"
@@ -835,12 +834,6 @@
       "dev": true,
       "license": "MIT"
     },
-    "node_modules/@types/history": {
-      "version": "4.7.11",
-      "resolved": "https://registry.npmjs.org/@types/history/-/history-4.7.11.tgz",
-      "integrity": "sha512-qjDJRrmvBMiTx+jyLxvLfJU7UznFuokDv4f3WRuriHKERccVpFU+8XMQUAbDzoiJCsmexxRExQeMwwCdamSKDA==",
-      "license": "MIT"
-    },
     "node_modules/@types/node": {
       "version": "25.5.2",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-25.5.2.tgz",
@@ -855,6 +848,7 @@
       "version": "19.2.14",
       "resolved": "https://registry.npmjs.org/@types/react/-/react-19.2.14.tgz",
       "integrity": "sha512-ilcTH/UniCkMdtexkoCN0bI7pMcJDvmQFPvuPvmEaYA/NSfFTAgdUSLAoVjaRJm7+6PvcM+q1zYOwS4wTYMF9w==",
+      "dev": true,
       "license": "MIT",
       "dependencies": {
         "csstype": "^3.2.2"
@@ -870,27 +864,6 @@
         "@types/react": "^19.2.0"
       }
     },
-    "node_modules/@types/react-router": {
-      "version": "5.1.20",
-      "resolved": "https://registry.npmjs.org/@types/react-router/-/react-router-5.1.20.tgz",
-      "integrity": "sha512-jGjmu/ZqS7FjSH6owMcD5qpq19+1RS9DeVRqfl1FeBMxTDQAGwlMWOcs52NDoXaNKyG3d1cYQFMs9rCrb88o9Q==",
-      "license": "MIT",
-      "dependencies": {
-        "@types/history": "^4.7.11",
-        "@types/react": "*"
-      }
-    },
-    "node_modules/@types/react-router-dom": {
-      "version": "5.3.3",
-      "resolved": "https://registry.npmjs.org/@types/react-router-dom/-/react-router-dom-5.3.3.tgz",
-      "integrity": "sha512-kpqnYK4wcdm5UaWI3fLcELopqLrHgLqNsdpHauzlQktfkHL3npOSwtj1Uz9oKBAzs7lFtVkV8j83voAz2D8fhw==",
-      "license": "MIT",
-      "dependencies": {
-        "@types/history": "^4.7.11",
-        "@types/react": "*",
-        "@types/react-router": "*"
-      }
-    },
     "node_modules/@vitejs/plugin-react": {
       "version": "6.0.1",
       "resolved": "https://registry.npmjs.org/@vitejs/plugin-react/-/plugin-react-6.0.1.tgz",
@@ -1162,6 +1135,7 @@
       "version": "3.2.3",
       "resolved": "https://registry.npmjs.org/csstype/-/csstype-3.2.3.tgz",
       "integrity": "sha512-z1HGKcYy2xA8AGQfwrn0PAy+PB7X/GSj3UVJW9qKyn43xWa+gl5nXmU4qqLMRzWVLFC8KusUX8T/0kCiOYpAIQ==",
+      "dev": true,
       "license": "MIT"
     },
     "node_modules/data-urls": {
diff --git a/web/src/pages/TimeOff.test.tsx b/web/src/pages/TimeOff.test.tsx
index a8ef385..c37e4b9 100644
--- a/web/src/pages/TimeOff.test.tsx
+++ b/web/src/pages/TimeOff.test.tsx
@@ -1,11 +1,12 @@
 import React from 'react';
 import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import { vi, type Mock } from 'vitest';
 import { MemoryRouter } from 'react-router-dom';
 import TimeOff from './TimeOff';
 import { api, TimeOffRequest, ApiError } from '../api';
 import { AuthProvider } from '../auth';
 
-jest.mock('../api', () => {
+vi.mock('../api', () => {
   class MockApiError extends Error {
     status: number;
     data: any;
@@ -17,24 +18,24 @@ jest.mock('../api', () => {
   }
   return {
     api: {
-      listTimeOff: jest.fn(),
-      createTimeOff: jest.fn(),
-      updateTimeOff: jest.fn(),
-      deleteTimeOff: jest.fn(),
-      reviewTimeOff: jest.fn(),
-      getRemovedShifts: jest.fn(),
-      listVolunteers: jest.fn(),
+      listTimeOff: vi.fn(),
+      createTimeOff: vi.fn(),
+      updateTimeOff: vi.fn(),
+      deleteTimeOff: vi.fn(),
+      reviewTimeOff: vi.fn(),
+      getRemovedShifts: vi.fn(),
+      listVolunteers: vi.fn(),
     },
     ApiError: MockApiError,
   };
 });
 
-const mockListTimeOff = api.listTimeOff as jest.Mock;
-const mockCreateTimeOff = api.createTimeOff as jest.Mock;
-const mockDeleteTimeOff = api.deleteTimeOff as jest.Mock;
-const mockReviewTimeOff = api.reviewTimeOff as jest.Mock;
-const mockGetRemovedShifts = api.getRemovedShifts as jest.Mock;
-const mockListVolunteers = api.listVolunteers as jest.Mock;
+const mockListTimeOff = api.listTimeOff as Mock;
+const mockCreateTimeOff = api.createTimeOff as Mock;
+const mockDeleteTimeOff = api.deleteTimeOff as Mock;
+const mockReviewTimeOff = api.reviewTimeOff as Mock;
+const mockGetRemovedShifts = api.getRemovedShifts as Mock;
+const mockListVolunteers = api.listVolunteers as Mock;
 
 function buildFakeJWT(payload: object): string {
   const header = btoa(JSON.stringify({ alg: 'HS256', typ: 'JWT' }));
@@ -90,7 +91,7 @@ function renderAsAdmin() {
 }
 
 beforeEach(() => {
-  jest.clearAllMocks();
+  vi.clearAllMocks();
   localStorage.clear();
   mockListVolunteers.mockResolvedValue([]);
 });
@@ -147,10 +148,10 @@ describe('TimeOff page', () => {
 
   it('shows conflict warning on 409 and allows confirmation', async () => {
     mockListTimeOff.mockResolvedValue([]);
-    const { ApiError: MockApiError } = jest.requireMock('../api');
+    const { ApiError: MockApiError } = await vi.importMock<typeof import('../api')>('../api');
     mockCreateTimeOff
       .mockRejectedValueOnce(
-        new MockApiError('conflict', 409, {
+        new (MockApiError as any)('conflict', 409, {
           message: 'Time off conflicts with assigned shifts.',
           conflicts: [
             { instance_id: 100, name: 'Morning Walk', date: '2026-06-01', start_time: '08:00', end_time: '12:00' },