diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..8e2347f
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,37 @@
+name: CI
+
+on:
+  pull_request:
+    branches: [ main, master ]
+  push:
+    branches: [ main, master ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [22.x]
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Setup Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v4
+      with:
+        node-version: ${{ matrix.node-version }}
+        cache: 'npm'
+
+    - name: Install dependencies
+      run: npm ci
+
+    - name: Run linter
+      run: npm run lint
+
+    - name: Run tests
+      run: npm test
+
+    - name: Run build
+      run: npm run build
diff --git a/.gitignore b/.gitignore
index e72a01e..889b6d7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,6 @@ tmp/
 .idea/
 *.iml
 node_modules/
-src/**/*.js
 
 # SASS
 .sass-cache
diff --git a/build.js b/build.js
index 03d0d8f..a9496c5 100644
--- a/build.js
+++ b/build.js
@@ -1,8 +1,8 @@
-const esbuild = require('esbuild');
-const { sassPlugin } = require('esbuild-sass-plugin');
-const fs = require('fs');
-const path = require('path');
-const PACKAGE = require('./package.json');
+import esbuild from 'esbuild';
+import { sassPlugin } from 'esbuild-sass-plugin';
+import fs from 'fs';
+import path from 'path';
+import PACKAGE from './package.json' with { type: 'json' };
 
 const ENV = process.env.WEBPACK_ENV;
 const libraryName = 'gh-profile-card';
@@ -12,7 +12,7 @@ const banner = `/**
 */
 `;
 
-const outfilePath = path.resolve(__dirname, 'dist', `${libraryName}.min.js`);
+const outfilePath = path.resolve('dist', `${libraryName}.min.js`);
 
 esbuild
   .build({
diff --git a/src/gh-cache-storage.spec.ts b/src/gh-cache-storage.spec.ts
index 54112f1..0419218 100644
--- a/src/gh-cache-storage.spec.ts
+++ b/src/gh-cache-storage.spec.ts
@@ -1,3 +1,4 @@
+import { beforeEach, describe, expect, it, jest } from '@jest/globals';
 import { CacheStorage, CacheEntry } from './gh-cache-storage';
 import { InMemoryStorage } from './testing/in-memory-storage';
 import { BrowserStorage } from './interface/storage';
diff --git a/src/gh-data-loader.spec.ts b/src/gh-data-loader.spec.ts
index a75af6c..e868724 100644
--- a/src/gh-data-loader.spec.ts
+++ b/src/gh-data-loader.spec.ts
@@ -1,3 +1,11 @@
+import {
+  beforeEach,
+  describe,
+  expect,
+  it,
+  afterEach,
+  jest,
+} from '@jest/globals';
 import { GitHubApiLoader } from './gh-data-loader';
 import { CacheStorage } from './gh-cache-storage';
 
@@ -168,15 +176,15 @@ describe('GitHubApiLoader', () => {
           headers: {
             get: jest.fn().mockReturnValue('Mon, 18 Mar 2019 20:40:35 GMT'),
           },
-          json: jest.fn().mockResolvedValue(mockProfile),
-        })
+          json: jest.fn(() => Promise.resolve(mockProfile)),
+        } as any)
         .mockResolvedValueOnce({
           status: 200,
           headers: {
             get: jest.fn().mockReturnValue('Mon, 18 Mar 2019 20:40:35 GMT'),
           },
-          json: jest.fn().mockResolvedValue(mockRepositories),
-        });
+          json: jest.fn(() => Promise.resolve(mockRepositories)),
+        } as any);
 
       // When
       const result = await loader.loadUserData('testuser');
@@ -242,7 +250,7 @@ describe('GitHubApiLoader', () => {
             );
             done();
           } catch (error) {
-            done(error);
+            done(error as Error);
           }
         },
       );
@@ -279,7 +287,7 @@ describe('GitHubApiLoader', () => {
             );
             done();
           } catch (error) {
-            done(error);
+            done(error as Error);
           }
         },
       );
diff --git a/src/gh-dom-operator.spec.ts b/src/gh-dom-operator.spec.ts
index 0307a67..8deee4b 100644
--- a/src/gh-dom-operator.spec.ts
+++ b/src/gh-dom-operator.spec.ts
@@ -1,3 +1,4 @@
+import { beforeEach, describe, expect, it } from '@jest/globals';
 import { DOMOperator } from './gh-dom-operator';
 import { ApiError, ApiProfile, ApiRepository } from './interface/IGitHubApi';
 
diff --git a/src/gh-dom.utils.spec.ts b/src/gh-dom.utils.spec.ts
index 6a5561b..da93300 100644
--- a/src/gh-dom.utils.spec.ts
+++ b/src/gh-dom.utils.spec.ts
@@ -1,3 +1,4 @@
+import { beforeEach, describe, expect, it } from '@jest/globals';
 import {
   createProfile,
   createName,
diff --git a/src/gh-profile-card.spec.ts b/src/gh-profile-card.spec.ts
index 7fecd8b..9415b52 100644
--- a/src/gh-profile-card.spec.ts
+++ b/src/gh-profile-card.spec.ts
@@ -1,3 +1,4 @@
+import { beforeEach, describe, expect, it, jest } from '@jest/globals';
 import { GitHubCardWidget } from './gh-profile-card';
 import { GitHubApiLoader } from './gh-data-loader';
 import { DOMOperator } from './gh-dom-operator';
diff --git a/src/gh-widget-init.spec.ts b/src/gh-widget-init.spec.ts
index c60d424..9bea632 100644
--- a/src/gh-widget-init.spec.ts
+++ b/src/gh-widget-init.spec.ts
@@ -1,4 +1,5 @@
-// Mock the GitHubCardWidget
+import { beforeEach, describe, expect, it, jest } from '@jest/globals';
+
 jest.mock('./gh-profile-card');
 
 import { GitHubCardWidget } from './gh-profile-card';
diff --git a/src/testing/fetch-mock.ts b/src/testing/fetch-mock.ts
index 3450680..7e57cd1 100644
--- a/src/testing/fetch-mock.ts
+++ b/src/testing/fetch-mock.ts
@@ -1,6 +1,5 @@
-/**
- * Fetch mock utilities for testing
- */
+import { jest } from '@jest/globals';
+import { ApiProfile, ApiRepository } from '../interface/IGitHubApi';
 
 export interface MockResponse {
   status: number;
@@ -25,8 +24,8 @@ export function setupFetchMock(): void {
 /**
  * Creates a successful HTTP response mock
  */
-export function createSuccessResponse(
-  data: any,
+export function createSuccessResponse<T>(
+  data: T,
   headers: Record<string, string> = {},
 ): MockResponse {
   return {
@@ -88,7 +87,10 @@ export function resetFetchMock(): void {
 /**
  * Sets up common fetch mock responses for user data loading
  */
-export function setupUserDataMocks(profile: any, repositories: any[]): void {
+export function setupUserDataMocks(
+  profile: ApiProfile,
+  repositories: ApiRepository[],
+): void {
   mockFetch
     .mockResolvedValueOnce(
       createSuccessResponse(profile, {
diff --git a/src/testing/style-mock.js b/src/testing/style-mock.js
new file mode 100644
index 0000000..f053ebf
--- /dev/null
+++ b/src/testing/style-mock.js
@@ -0,0 +1 @@
+module.exports = {};
diff --git a/src/testing/test-setup.ts b/src/testing/test-setup.ts
index 5c11dd0..fe3c9c2 100644
--- a/src/testing/test-setup.ts
+++ b/src/testing/test-setup.ts
@@ -1,4 +1,4 @@
-// import { jest } from '@jest/globals';
+import { jest, beforeEach, expect, afterEach } from '@jest/globals';
 
 // Mock console methods during tests to reduce noise
 const originalError = console.error;
diff --git a/tsconfig.json b/tsconfig.json
index f8b000d..b72571a 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,11 +2,18 @@
   "compilerOptions": {
     "outDir": "./dist/",
     "noImplicitAny": false,
-    "module": "es2015",
+    "module": "es2022",
     "target": "es2017",
     "sourceMap": true,
     "allowJs": true,
     "esModuleInterop": true,
-    "allowSyntheticDefaultImports": true
-  }
+    "allowSyntheticDefaultImports": true,
+    "moduleResolution": "nodenext",
+    "strict": false,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "types": ["jest", "node"]
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
 }