diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..d325e2a
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,48 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+jobs:
+  test:
+    name: Run Tests & Build
+    runs-on: ubuntu-latest
+
+    services:
+      mongodb:
+        image: mongo:6.0
+        ports:
+          - 27017:27017
+        options: >-
+          --health-cmd="mongosh --eval 'db.adminCommand(\"ping\")'"
+          --health-interval=10s
+          --health-timeout=5s
+          --health-retries=5
+
+    env:
+      MONGO_URL: mongodb://127.0.0.1:27017/worlddriven_test
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Auto format with Prettier
+        run: npm run format
+
+      - name: Run tests
+        run: npm test
+
+      - name: Build project
+        run: npm run build
diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 218475d..1fe69c3 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -8,12 +8,12 @@ jobs:
   deploy:
     name: Deploy to Production
     runs-on: ubuntu-latest
-    
+
     steps:
       - name: Deploy to Dokku
         run: |
           echo "Triggering deployment for commit ${{ github.sha }}"
-          
+
           response=$(curl -s -w "%{http_code}" -o response.json \
             -X POST https://sumalyze.tooangel.com/deploy/worlddriven \
             -H "Authorization: Bearer ${{ secrets.DEPLOY_WEBHOOK_SECRET }}" \
@@ -23,32 +23,32 @@ jobs:
               "commit": "${{ github.sha }}",
               "branch": "${{ github.ref_name }}"
             }')
-          
+
           http_code="${response: -3}"
-          
+
           echo "HTTP Status Code: $http_code"
           echo "Response:"
           cat response.json
-          
+
           if [ "$http_code" -ne 200 ]; then
             echo "Deployment failed with HTTP status: $http_code"
             exit 1
           fi
-          
+
           echo "Deployment triggered successfully!"
 
       - name: Verify Deployment
         run: |
           echo "Waiting 30 seconds for deployment to complete..."
           sleep 30
-          
+
           echo "Checking if worlddriven service is responding..."
           response=$(curl -s -w "%{http_code}" -o health.json https://www.worlddriven.org/ || echo "000")
           http_code="${response: -3}"
-          
+
           if [ "$http_code" = "200" ]; then
             echo "✅ Deployment successful - worlddriven is responding"
           else
             echo "⚠️  Warning: worlddriven may still be starting (HTTP $http_code)"
             echo "This doesn't necessarily mean deployment failed."
-          fi
\ No newline at end of file
+          fi
diff --git a/GITHUB_APP_MIGRATION.md b/GITHUB_APP_MIGRATION.md
new file mode 100644
index 0000000..a00c794
--- /dev/null
+++ b/GITHUB_APP_MIGRATION.md
@@ -0,0 +1,180 @@
+# GitHub App Migration Guide
+
+This document outlines the migration from Personal Access Token (PAT) authentication to GitHub App authentication in World Driven.
+
+## Overview
+
+World Driven now supports both Personal Access Token (PAT) and GitHub App authentication methods. This hybrid approach allows for gradual migration while maintaining backward compatibility.
+
+## Benefits of GitHub App Authentication
+
+1. **Multi-owner resilience** - Survives individual user departures
+2. **Better security** - Fine-grained permissions per repository
+3. **Automatic token management** - No expired tokens to manage
+4. **Organization support** - Works seamlessly with GitHub organizations
+5. **Official GitHub recommendation** - Future-proof approach
+
+## Architecture Changes
+
+### Database Schema
+
+The `repositories` collection now includes an `installationId` field:
+
+```javascript
+{
+  _id: ObjectId(),
+  owner: "TooAngel",
+  repo: "screeps",
+  userId: ObjectId() || null,        // Legacy PAT authentication
+  installationId: 12345678 || null,  // GitHub App authentication
+  configured: true,
+  createdAt: Date,
+  updatedAt: Date
+}
+```
+
+### Authentication Flow
+
+The system automatically detects the authentication method for each repository:
+
+1. **GitHub App**: If `installationId` is present, uses GitHub App authentication
+2. **PAT (Legacy)**: If `userId` is present, uses Personal Access Token authentication
+3. **Error**: If neither is present, logs an error and skips the repository
+
+### Hybrid API Functions
+
+All GitHub API functions in `src/helpers/github.js` now accept either:
+- A user object (for PAT authentication)
+- An installation ID number (for GitHub App authentication)
+
+Example:
+```javascript
+// PAT authentication
+await getPullRequests(userObject, owner, repo);
+
+// GitHub App authentication
+await getPullRequests(installationId, owner, repo);
+```
+
+## Environment Variables
+
+Add these new environment variables for GitHub App support:
+
+```bash
+# GitHub App Configuration
+GITHUB_APP_ID=your_app_id
+GITHUB_APP_PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----..."
+GITHUB_WEBHOOK_SECRET=your_webhook_secret
+GITHUB_APP_NAME=world-driven  # Optional, for installation URL
+
+# Keep existing OAuth for backward compatibility
+GITHUB_CLIENT_ID=existing_oauth_client_id
+GITHUB_CLIENT_SECRET=existing_oauth_secret
+```
+
+## Installation and Usage
+
+### For GitHub App (Recommended)
+
+1. Visit `/install-app` to install the World Driven GitHub App
+2. Select repositories to enable World Driven on
+3. Repositories will be automatically configured with GitHub App authentication
+
+### For PAT (Legacy)
+
+1. Visit `/login` to authenticate with Personal Access Token
+2. Use the dashboard to enable World Driven on repositories
+3. Repositories will use PAT authentication
+
+## Migration Process
+
+### Automatic Migration
+
+When the GitHub App is installed on repositories that already exist in the database (from PAT setup), the system automatically:
+
+1. Updates the repository record to include `installationId`
+2. Keeps the existing `userId` for backward compatibility
+3. Switches to GitHub App authentication for all operations
+
+### Manual Migration
+
+To migrate existing PAT repositories to GitHub App:
+
+1. Install the GitHub App on your account/organization
+2. Select the repositories you want to migrate
+3. The webhook handlers will automatically update the database
+
+### Database Migration
+
+Run the migration script to add the `installationId` field to existing repositories:
+
+```bash
+node scripts/add-installation-field.js
+```
+
+## Webhook Events
+
+The GitHub App handles additional webhook events:
+
+- `installation` - App installed/uninstalled
+- `installation_repositories` - Repositories added/removed from installation
+- `pull_request` - Pull request events (existing)
+- `pull_request_review` - Review events (existing)
+- `push` - Push events (existing)
+
+## Monitoring
+
+The application logs authentication method for each repository during processing:
+
+```
+Using GitHub App authentication (installation: 12345678)
+Using PAT authentication (user: 507f1f77bcf86cd799439011)
+```
+
+## Backward Compatibility
+
+- Existing PAT-authenticated repositories continue to work unchanged
+- OAuth login flow remains available at `/login`
+- All existing API endpoints continue to function
+- No breaking changes to existing functionality
+
+## Future Migration
+
+Once all repositories are migrated to GitHub App authentication:
+
+1. The `userId` field can be removed from the database schema
+2. PAT authentication code can be removed
+3. OAuth login flow can be deprecated
+4. The `users` collection can be removed
+
+## Troubleshooting
+
+### Repository Not Processing
+
+Check the authentication method in logs:
+- If "No authentication method configured", add either `installationId` or `userId`
+- If "No user found", the referenced user doesn't exist in the database
+- If "HTTP 401: Unauthorized", the token/installation has insufficient permissions
+
+### GitHub App Installation Issues
+
+1. Verify the app is installed on the repository owner's account
+2. Check that the repository is included in the installation
+3. Ensure webhook URL is correctly configured
+4. Verify environment variables are set correctly
+
+### Token Issues
+
+- GitHub App tokens are automatically managed and refresh
+- PAT tokens may expire and need manual renewal
+- Check GitHub App permissions if operations fail
+
+## Testing
+
+Test both authentication methods:
+
+1. Install GitHub App on a test repository
+2. Verify webhook events are received and processed
+3. Check that pull requests are processed correctly
+4. Ensure existing PAT repositories continue working
+5. Test migration from PAT to GitHub App authentication
\ No newline at end of file
diff --git a/package-lock.json b/package-lock.json
index 5425f34..973d0a8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,6 +9,9 @@
       "version": "1.0.0",
       "license": "AGPL",
       "dependencies": {
+        "@octokit/auth-app": "^8.1.0",
+        "@octokit/rest": "^22.0.0",
+        "@octokit/webhooks": "^14.1.3",
         "connect-mongo": "5.1.0",
         "express": "4.21.2",
         "express-session": "1.18.2",
@@ -808,6 +811,279 @@
         "sparse-bitfield": "^3.0.3"
       }
     },
+    "node_modules/@octokit/auth-app": {
+      "version": "8.1.0",
+      "resolved": "https://registry.npmjs.org/@octokit/auth-app/-/auth-app-8.1.0.tgz",
+      "integrity": "sha512-6bWhyvLXqCSfHiqlwzn9pScLZ+Qnvh/681GR/UEEPCMIVwfpRDBw0cCzy3/t2Dq8B7W2X/8pBgmw6MOiyE0DXQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/auth-oauth-app": "^9.0.1",
+        "@octokit/auth-oauth-user": "^6.0.0",
+        "@octokit/request": "^10.0.2",
+        "@octokit/request-error": "^7.0.0",
+        "@octokit/types": "^14.0.0",
+        "toad-cache": "^3.7.0",
+        "universal-github-app-jwt": "^2.2.0",
+        "universal-user-agent": "^7.0.0"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
+    "node_modules/@octokit/auth-oauth-app": {
+      "version": "9.0.1",
+      "resolved": "https://registry.npmjs.org/@octokit/auth-oauth-app/-/auth-oauth-app-9.0.1.tgz",
+      "integrity": "sha512-TthWzYxuHKLAbmxdFZwFlmwVyvynpyPmjwc+2/cI3cvbT7mHtsAW9b1LvQaNnAuWL+pFnqtxdmrU8QpF633i1g==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/auth-oauth-device": "^8.0.1",
+        "@octokit/auth-oauth-user": "^6.0.0",
+        "@octokit/request": "^10.0.2",
+        "@octokit/types": "^14.0.0",
+        "universal-user-agent": "^7.0.0"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
+    "node_modules/@octokit/auth-oauth-device": {
+      "version": "8.0.1",
+      "resolved": "https://registry.npmjs.org/@octokit/auth-oauth-device/-/auth-oauth-device-8.0.1.tgz",
+      "integrity": "sha512-TOqId/+am5yk9zor0RGibmlqn4V0h8vzjxlw/wYr3qzkQxl8aBPur384D1EyHtqvfz0syeXji4OUvKkHvxk/Gw==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/oauth-methods": "^6.0.0",
+        "@octokit/request": "^10.0.2",
+        "@octokit/types": "^14.0.0",
+        "universal-user-agent": "^7.0.0"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
+    "node_modules/@octokit/auth-oauth-user": {
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/@octokit/auth-oauth-user/-/auth-oauth-user-6.0.0.tgz",
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+      "license": "MIT",
+      "dependencies": {
+        "@octokit/auth-oauth-device": "^8.0.1",
+        "@octokit/oauth-methods": "^6.0.0",
+        "@octokit/request": "^10.0.2",
+        "@octokit/types": "^14.0.0",
+        "universal-user-agent": "^7.0.0"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
+    "node_modules/@octokit/auth-token": {
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/@octokit/auth-token/-/auth-token-6.0.0.tgz",
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+      "license": "MIT",
+      "engines": {
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+      }
+    },
+    "node_modules/@octokit/core": {
+      "version": "7.0.3",
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+      "license": "MIT",
+      "dependencies": {
+        "@octokit/auth-token": "^6.0.0",
+        "@octokit/graphql": "^9.0.1",
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+        "@octokit/types": "^14.0.0",
+        "before-after-hook": "^4.0.0",
+        "universal-user-agent": "^7.0.0"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
+    "node_modules/@octokit/endpoint": {
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+      },
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+      "license": "MIT",
+      "engines": {
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+      }
+    },
+    "node_modules/@octokit/oauth-methods": {
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+      "license": "MIT",
+      "dependencies": {
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+    },
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+    },
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+      },
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+      }
+    },
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+        "@octokit/openapi-webhooks-types": "12.0.3",
+        "@octokit/request-error": "^7.0.0",
+        "@octokit/webhooks-methods": "^6.0.0"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
+    "node_modules/@octokit/webhooks-methods": {
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/@octokit/webhooks-methods/-/webhooks-methods-6.0.0.tgz",
+      "integrity": "sha512-MFlzzoDJVw/GcbfzVC1RLR36QqkTLUf79vLVO3D+xn7r0QgxnFoLZgtrzxiQErAjFUOdH6fas2KeQJ1yr/qaXQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 20"
+      }
+    },
     "node_modules/@rollup/rollup-linux-x64-gnu": {
       "version": "4.50.0",
       "resolved": "https://registry.npmjs.org/@rollup/rollup-linux-x64-gnu/-/rollup-linux-x64-gnu-4.50.0.tgz",
@@ -1248,6 +1524,12 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/before-after-hook": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/before-after-hook/-/before-after-hook-4.0.0.tgz",
+      "integrity": "sha512-q6tR3RPqIB1pMiTRMFcZwuG5T8vwp+vUvEG0vuI6B+Rikh5BfPp2fQ82c925FOs+b0lcFQ8CFrL+KbilfZFhOQ==",
+      "license": "Apache-2.0"
+    },
     "node_modules/bn.js": {
       "version": "4.12.2",
       "resolved": "https://registry.npmjs.org/bn.js/-/bn.js-4.12.2.tgz",
@@ -2678,6 +2960,22 @@
         "tmp": "^0.0.29"
       }
     },
+    "node_modules/fast-content-type-parse": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/fast-content-type-parse/-/fast-content-type-parse-3.0.0.tgz",
+      "integrity": "sha512-ZvLdcY8P+N8mGQJahJV5G4U88CSvT1rP8ApL6uETe88MBXrBHAkZlSEySdUlyztF7ccb+Znos3TFqaepHxdhBg==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/fastify"
+        },
+        {
+          "type": "opencollective",
+          "url": "https://opencollective.com/fastify"
+        }
+      ],
+      "license": "MIT"
+    },
     "node_modules/fast-deep-equal": {
       "version": "3.1.3",
       "resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
@@ -5848,6 +6146,15 @@
         "node": ">=0.4.0"
       }
     },
+    "node_modules/toad-cache": {
+      "version": "3.7.0",
+      "resolved": "https://registry.npmjs.org/toad-cache/-/toad-cache-3.7.0.tgz",
+      "integrity": "sha512-/m8M+2BJUpoJdgAHoG+baCwBT+tf2VraSfkBgl0Y00qIWt41DJ8R5B8nsEw0I58YwF5IZH6z24/2TobDKnqSWw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=12"
+      }
+    },
     "node_modules/toidentifier": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/toidentifier/-/toidentifier-1.0.1.tgz",
@@ -6045,6 +6352,18 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/universal-github-app-jwt": {
+      "version": "2.2.2",
+      "resolved": "https://registry.npmjs.org/universal-github-app-jwt/-/universal-github-app-jwt-2.2.2.tgz",
+      "integrity": "sha512-dcmbeSrOdTnsjGjUfAlqNDJrhxXizjAz94ija9Qw8YkZ1uu0d+GoZzyH+Jb9tIIqvGsadUfwg+22k5aDqqwzbw==",
+      "license": "MIT"
+    },
+    "node_modules/universal-user-agent": {
+      "version": "7.0.3",
+      "resolved": "https://registry.npmjs.org/universal-user-agent/-/universal-user-agent-7.0.3.tgz",
+      "integrity": "sha512-TmnEAEAsBJVZM/AADELsK76llnwcf9vMKuPz8JflO1frO8Lchitr0fNaN9d+Ap0BjKtqWqd/J17qeDnXh8CL2A==",
+      "license": "ISC"
+    },
     "node_modules/unpipe": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/unpipe/-/unpipe-1.0.0.tgz",
diff --git a/package.json b/package.json
index b800abc..c0b49b4 100644
--- a/package.json
+++ b/package.json
@@ -25,9 +25,13 @@
     "lint": "eslint . --report-unused-disable-directives --max-warnings 0",
     "lint:frontend": "eslint static/js --config frontend.eslint.config.cjs --report-unused-disable-directives --max-warnings 0",
     "start": "node src/index.js",
-    "test": "npm run check && sort-package-json package.json --check && mdspell --en-us --ignore-numbers --report \"*.md\" && write-good --no-adverb README.md CONTRIBUTING.md"
+    "test": "npm run check && sort-package-json package.json --check && mdspell --en-us --ignore-numbers --report \"*.md\" && write-good --no-adverb README.md CONTRIBUTING.md",
+    "format": "prettier --write ."
   },
   "dependencies": {
+    "@octokit/auth-app": "^8.1.0",
+    "@octokit/rest": "^22.0.0",
+    "@octokit/webhooks": "^14.1.3",
     "connect-mongo": "5.1.0",
     "express": "4.21.2",
     "express-session": "1.18.2",
diff --git a/scripts/add-installation-field.js b/scripts/add-installation-field.js
new file mode 100644
index 0000000..7d3f4c9
--- /dev/null
+++ b/scripts/add-installation-field.js
@@ -0,0 +1,44 @@
+#!/usr/bin/env node
+
+import { database, client } from '../src/database/database.js';
+
+async function migrateDatabase() {
+  try {
+    console.log('Starting database migration: Adding installationId field...');
+
+    // Add installationId field to all existing repositories
+    const result = await database.repositories.updateMany(
+      { installationId: { $exists: false } },
+      { $set: { installationId: null } }
+    );
+
+    console.log(
+      `Migration complete: Updated ${result.modifiedCount} repositories with installationId field`
+    );
+
+    // Show current repository status
+    const repos = await database.repositories.find({}).toArray();
+    console.log('\nCurrent repository authentication status:');
+    for (const repo of repos) {
+      const authType = repo.installationId
+        ? 'GitHub App'
+        : repo.userId
+          ? 'PAT'
+          : 'None';
+      console.log(
+        `- ${repo.owner}/${repo.repo}: ${authType} (configured: ${repo.configured})`
+      );
+    }
+  } catch (error) {
+    console.error('Migration failed:', error);
+    process.exit(1);
+  } finally {
+    await client.close();
+  }
+}
+
+if (import.meta.url === `file://${process.argv[1]}`) {
+  migrateDatabase();
+}
+
+export { migrateDatabase };
diff --git a/src/database/models.js b/src/database/models.js
index c48b180..8e885c4 100644
--- a/src/database/models.js
+++ b/src/database/models.js
@@ -74,16 +74,19 @@ export const Repository = {
    * @param {string} repoData.owner
    * @param {string} repoData.repo
    * @param {boolean} repoData.configured
-   * @param {string|ObjectId} repoData.userId
+   * @param {string|ObjectId} [repoData.userId] - Legacy PAT authentication
+   * @param {number} [repoData.installationId] - GitHub App authentication
    * @returns {Promise<import('./database.js').Repository>}
    */
   async create(repoData) {
     const repository = {
       ...repoData,
-      userId:
-        typeof repoData.userId === 'string'
+      userId: repoData.userId
+        ? typeof repoData.userId === 'string'
           ? new ObjectId(repoData.userId)
-          : repoData.userId,
+          : repoData.userId
+        : null,
+      installationId: repoData.installationId || null,
       createdAt: new Date(),
       updatedAt: new Date(),
     };
@@ -129,6 +132,15 @@ export const Repository = {
     return await database.repositories.find({ userId: objectId }).toArray();
   },
 
+  /**
+   * Find repositories by installation ID
+   * @param {number} installationId
+   * @returns {Promise<import('./database.js').Repository[]>}
+   */
+  async findByInstallationId(installationId) {
+    return await database.repositories.find({ installationId }).toArray();
+  },
+
   /**
    * Find all repositories
    * @returns {Promise<import('./database.js').Repository[]>}
@@ -155,6 +167,9 @@ export const Repository = {
           ? new ObjectId(updates.userId)
           : updates.userId;
     }
+    if (updates.installationId !== undefined) {
+      updateData.installationId = updates.installationId;
+    }
     await database.repositories.updateOne(
       { _id: objectId },
       { $set: updateData }
diff --git a/src/helpers/github.js b/src/helpers/github.js
index 4c6af8c..a2505ce 100644
--- a/src/helpers/github.js
+++ b/src/helpers/github.js
@@ -1,14 +1,37 @@
 // Using native fetch API
+import {
+  getPullRequestsApp,
+  mergePullRequestApp,
+  setCommitStatusApp,
+  getLatestCommitShaApp,
+  createIssueCommentApp,
+  createWebhookApp,
+  deleteWebhookApp,
+} from './githubApp.js';
 
 /**
- * getPullRequests
+ * getPullRequests - Hybrid authentication (GitHub App or PAT)
  *
- * @param {object} user
+ * @param {object|number} userOrInstallationId - User object with githubAccessToken or installationId number
  * @param {string} owner
  * @param {string} repo
  * @return {void}
  */
-export async function getPullRequests(user, owner, repo) {
+export async function getPullRequests(userOrInstallationId, owner, repo) {
+  // If it's a number, treat as installationId (GitHub App)
+  if (
+    typeof userOrInstallationId === 'number' ||
+    (typeof userOrInstallationId === 'string' && !isNaN(userOrInstallationId))
+  ) {
+    return await getPullRequestsApp(
+      parseInt(userOrInstallationId),
+      owner,
+      repo
+    );
+  }
+
+  // Otherwise, use existing PAT logic
+  const user = userOrInstallationId;
   const url = `https://api.github.com/repos/${owner}/${repo}/pulls?state=open`;
 
   try {
@@ -41,15 +64,35 @@ export async function getPullRequests(user, owner, repo) {
 }
 
 /**
- * mergePullRequest
+ * mergePullRequest - Hybrid authentication (GitHub App or PAT)
  *
- * @param {object} user
+ * @param {object|number} userOrInstallationId - User object with githubAccessToken or installationId number
  * @param {string} owner
  * @param {string} repo
  * @param {number} number
  * @return {void}
  */
-export async function mergePullRequest(user, owner, repo, number) {
+export async function mergePullRequest(
+  userOrInstallationId,
+  owner,
+  repo,
+  number
+) {
+  // If it's a number, treat as installationId (GitHub App)
+  if (
+    typeof userOrInstallationId === 'number' ||
+    (typeof userOrInstallationId === 'string' && !isNaN(userOrInstallationId))
+  ) {
+    return await mergePullRequestApp(
+      parseInt(userOrInstallationId),
+      owner,
+      repo,
+      number
+    );
+  }
+
+  // Otherwise, use existing PAT logic
+  const user = userOrInstallationId;
   const url = `https://api.github.com/repos/${owner}/${repo}/pulls/${number}/merge`;
 
   try {
@@ -77,16 +120,38 @@ export async function mergePullRequest(user, owner, repo, number) {
 }
 
 /**
- * createIssueComment
+ * createIssueComment - Hybrid authentication (GitHub App or PAT)
  *
- * @param {object} user
+ * @param {object|number} userOrInstallationId - User object with githubAccessToken or installationId number
  * @param {string} owner
  * @param {string} repo
  * @param {number} number
  * @param {string} comment
  * @return {void}
  */
-export async function createIssueComment(user, owner, repo, number, comment) {
+export async function createIssueComment(
+  userOrInstallationId,
+  owner,
+  repo,
+  number,
+  comment
+) {
+  // If it's a number, treat as installationId (GitHub App)
+  if (
+    typeof userOrInstallationId === 'number' ||
+    (typeof userOrInstallationId === 'string' && !isNaN(userOrInstallationId))
+  ) {
+    return await createIssueCommentApp(
+      parseInt(userOrInstallationId),
+      owner,
+      repo,
+      number,
+      comment
+    );
+  }
+
+  // Otherwise, use existing PAT logic
+  const user = userOrInstallationId;
   const url = `https://api.github.com/repos/${owner}/${repo}/issues/${number}/comments`;
 
   try {
@@ -114,9 +179,9 @@ export async function createIssueComment(user, owner, repo, number, comment) {
 }
 
 /**
- * setCommitStatus
+ * setCommitStatus - Hybrid authentication (GitHub App or PAT)
  *
- * @param {object} user
+ * @param {object|number} userOrInstallationId - User object with githubAccessToken or installationId number
  * @param {string} owner
  * @param {string} repo
  * @param {string} sha - commit SHA
@@ -127,7 +192,7 @@ export async function createIssueComment(user, owner, repo, number, comment) {
  * @return {void}
  */
 export async function setCommitStatus(
-  user,
+  userOrInstallationId,
   owner,
   repo,
   sha,
@@ -136,6 +201,25 @@ export async function setCommitStatus(
   description,
   context = 'World driven'
 ) {
+  // If it's a number, treat as installationId (GitHub App)
+  if (
+    typeof userOrInstallationId === 'number' ||
+    (typeof userOrInstallationId === 'string' && !isNaN(userOrInstallationId))
+  ) {
+    return await setCommitStatusApp(
+      parseInt(userOrInstallationId),
+      owner,
+      repo,
+      sha,
+      state,
+      targetUrl,
+      description,
+      context
+    );
+  }
+
+  // Otherwise, use existing PAT logic
+  const user = userOrInstallationId;
   const url = `https://api.github.com/repos/${owner}/${repo}/statuses/${sha}`;
 
   try {
@@ -172,15 +256,35 @@ export async function setCommitStatus(
 }
 
 /**
- * getLatestCommitSha
+ * getLatestCommitSha - Hybrid authentication (GitHub App or PAT)
  *
- * @param {object} user
+ * @param {object|number} userOrInstallationId - User object with githubAccessToken or installationId number
  * @param {string} owner
  * @param {string} repo
  * @param {number} pullNumber
  * @return {string} commit SHA
  */
-export async function getLatestCommitSha(user, owner, repo, pullNumber) {
+export async function getLatestCommitSha(
+  userOrInstallationId,
+  owner,
+  repo,
+  pullNumber
+) {
+  // If it's a number, treat as installationId (GitHub App)
+  if (
+    typeof userOrInstallationId === 'number' ||
+    (typeof userOrInstallationId === 'string' && !isNaN(userOrInstallationId))
+  ) {
+    return await getLatestCommitShaApp(
+      parseInt(userOrInstallationId),
+      owner,
+      repo,
+      pullNumber
+    );
+  }
+
+  // Otherwise, use existing PAT logic
+  const user = userOrInstallationId;
   const url = `https://api.github.com/repos/${owner}/${repo}/pulls/${pullNumber}/commits`;
 
   try {
@@ -210,15 +314,35 @@ export async function getLatestCommitSha(user, owner, repo, pullNumber) {
 }
 
 /**
- * createWebhook - Create a GitHub webhook for a repository
+ * createWebhook - Create a GitHub webhook for a repository - Hybrid authentication (GitHub App or PAT)
  *
- * @param {object} user
+ * @param {object|number} userOrInstallationId - User object with githubAccessToken or installationId number
  * @param {string} owner
  * @param {string} repo
  * @param {string} webhookUrl - The URL to receive webhooks
  * @return {object} webhook response
  */
-export async function createWebhook(user, owner, repo, webhookUrl) {
+export async function createWebhook(
+  userOrInstallationId,
+  owner,
+  repo,
+  webhookUrl
+) {
+  // If it's a number, treat as installationId (GitHub App)
+  if (
+    typeof userOrInstallationId === 'number' ||
+    (typeof userOrInstallationId === 'string' && !isNaN(userOrInstallationId))
+  ) {
+    return await createWebhookApp(
+      parseInt(userOrInstallationId),
+      owner,
+      repo,
+      webhookUrl
+    );
+  }
+
+  // Otherwise, use existing PAT logic
+  const user = userOrInstallationId;
   const url = `https://api.github.com/repos/${owner}/${repo}/hooks`;
 
   const webhookConfig = {
@@ -267,15 +391,35 @@ export async function createWebhook(user, owner, repo, webhookUrl) {
 }
 
 /**
- * deleteWebhook - Delete GitHub webhooks for a repository
+ * deleteWebhook - Delete GitHub webhooks for a repository - Hybrid authentication (GitHub App or PAT)
  *
- * @param {object} user
+ * @param {object|number} userOrInstallationId - User object with githubAccessToken or installationId number
  * @param {string} owner
  * @param {string} repo
  * @param {string} webhookUrl - The webhook URL to delete
  * @return {void}
  */
-export async function deleteWebhook(user, owner, repo, webhookUrl) {
+export async function deleteWebhook(
+  userOrInstallationId,
+  owner,
+  repo,
+  webhookUrl
+) {
+  // If it's a number, treat as installationId (GitHub App)
+  if (
+    typeof userOrInstallationId === 'number' ||
+    (typeof userOrInstallationId === 'string' && !isNaN(userOrInstallationId))
+  ) {
+    return await deleteWebhookApp(
+      parseInt(userOrInstallationId),
+      owner,
+      repo,
+      webhookUrl
+    );
+  }
+
+  // Otherwise, use existing PAT logic
+  const user = userOrInstallationId;
   const url = `https://api.github.com/repos/${owner}/${repo}/hooks`;
 
   try {
diff --git a/src/helpers/githubApp.js b/src/helpers/githubApp.js
new file mode 100644
index 0000000..e2833e3
--- /dev/null
+++ b/src/helpers/githubApp.js
@@ -0,0 +1,214 @@
+import { createAppAuth } from '@octokit/auth-app';
+import { Octokit } from '@octokit/rest';
+
+// App-level client for managing installations (reserved for future use)
+// const appOctokit = new Octokit({
+//   authStrategy: createAppAuth,
+//   auth: {
+//     appId: process.env.GITHUB_APP_ID,
+//     privateKey: process.env.GITHUB_APP_PRIVATE_KEY,
+//   },
+// });
+
+// Installation-level client for repository operations
+export async function getInstallationOctokit(installationId) {
+  return new Octokit({
+    authStrategy: createAppAuth,
+    auth: {
+      appId: process.env.GITHUB_APP_ID,
+      privateKey: process.env.GITHUB_APP_PRIVATE_KEY,
+      installationId: parseInt(installationId),
+    },
+  });
+}
+
+// GitHub App API functions
+export async function getPullRequestsApp(installationId, owner, repo) {
+  const octokit = await getInstallationOctokit(installationId);
+  const { data } = await octokit.rest.pulls.list({
+    owner,
+    repo,
+    state: 'open',
+  });
+
+  return data.map(pull => ({
+    id: pull.id,
+    title: pull.title,
+    number: pull.number,
+  }));
+}
+
+export async function mergePullRequestApp(installationId, owner, repo, number) {
+  const octokit = await getInstallationOctokit(installationId);
+  try {
+    return await octokit.rest.pulls.merge({
+      owner,
+      repo,
+      pull_number: number,
+    });
+  } catch (error) {
+    if (error.status === 405) return; // Cannot merge
+    throw error;
+  }
+}
+
+export async function setCommitStatusApp(
+  installationId,
+  owner,
+  repo,
+  sha,
+  state,
+  targetUrl,
+  description,
+  context = 'World driven'
+) {
+  const octokit = await getInstallationOctokit(installationId);
+  try {
+    const response = await octokit.rest.repos.createCommitStatus({
+      owner,
+      repo,
+      sha,
+      state,
+      target_url: targetUrl,
+      description,
+      context,
+    });
+    console.log(
+      `✅ Set status for ${owner}/${repo}@${sha}: ${state} - ${description}`
+    );
+    return response;
+  } catch (error) {
+    console.error(
+      `❌ Failed to set status for ${owner}/${repo}@${sha}:`,
+      error.message
+    );
+    throw error;
+  }
+}
+
+export async function getLatestCommitShaApp(
+  installationId,
+  owner,
+  repo,
+  pullNumber
+) {
+  const octokit = await getInstallationOctokit(installationId);
+  try {
+    const { data: commits } = await octokit.rest.pulls.listCommits({
+      owner,
+      repo,
+      pull_number: pullNumber,
+    });
+
+    if (commits.length === 0) {
+      throw new Error('No commits found for pull request');
+    }
+    return commits[commits.length - 1].sha;
+  } catch (error) {
+    console.error(
+      `❌ Failed to get commits for PR ${owner}/${repo}#${pullNumber}:`,
+      error.message
+    );
+    throw error;
+  }
+}
+
+export async function createIssueCommentApp(
+  installationId,
+  owner,
+  repo,
+  number,
+  comment
+) {
+  const octokit = await getInstallationOctokit(installationId);
+  try {
+    return await octokit.rest.issues.createComment({
+      owner,
+      repo,
+      issue_number: number,
+      body: comment,
+    });
+  } catch (error) {
+    console.error(
+      `❌ Failed to create comment for ${owner}/${repo}#${number}:`,
+      error.message
+    );
+    throw error;
+  }
+}
+
+export async function createWebhookApp(
+  installationId,
+  owner,
+  repo,
+  webhookUrl
+) {
+  const octokit = await getInstallationOctokit(installationId);
+
+  const webhookConfig = {
+    url: webhookUrl,
+    insecure_ssl: '0',
+    content_type: 'json',
+  };
+
+  const events = ['pull_request', 'pull_request_review', 'push'];
+
+  try {
+    const response = await octokit.rest.repos.createWebhook({
+      owner,
+      repo,
+      name: 'web',
+      config: webhookConfig,
+      events: events,
+      active: true,
+    });
+
+    console.log(`✅ Created webhook for ${owner}/${repo} -> ${webhookUrl}`);
+    return response.data;
+  } catch (error) {
+    // If webhook already exists, that's okay
+    if (error.status === 422) {
+      console.log(`Webhook already exists for ${owner}/${repo}`);
+      return { info: 'Webhook already exists' };
+    }
+    console.error(
+      `❌ Failed to create webhook for ${owner}/${repo}:`,
+      error.message
+    );
+    throw error;
+  }
+}
+
+export async function deleteWebhookApp(
+  installationId,
+  owner,
+  repo,
+  webhookUrl
+) {
+  const octokit = await getInstallationOctokit(installationId);
+
+  try {
+    // First, get all hooks
+    const { data: hooks } = await octokit.rest.repos.listWebhooks({
+      owner,
+      repo,
+    });
+
+    // Find hooks that match our webhook URL
+    for (const hook of hooks) {
+      if (hook.config && hook.config.url === webhookUrl) {
+        await octokit.rest.repos.deleteWebhook({
+          owner,
+          repo,
+          hook_id: hook.id,
+        });
+        console.log(`✅ Deleted webhook ${hook.id} for ${owner}/${repo}`);
+      }
+    }
+  } catch (error) {
+    console.error(
+      `❌ Failed to delete webhooks for ${owner}/${repo}:`,
+      error.message
+    );
+  }
+}
diff --git a/src/helpers/installationHandler.js b/src/helpers/installationHandler.js
new file mode 100644
index 0000000..d146fd5
--- /dev/null
+++ b/src/helpers/installationHandler.js
@@ -0,0 +1,108 @@
+import { Repository } from '../database/models.js';
+
+/**
+ * Handle GitHub App installation webhook
+ * @param {object} payload
+ */
+export async function handleInstallationWebhook(payload) {
+  const { action, installation, repositories } = payload;
+
+  if (action === 'created') {
+    console.log(
+      `GitHub App installed by ${installation.account.login} (ID: ${installation.id})`
+    );
+
+    // Auto-configure repositories if specific repos were selected
+    if (repositories) {
+      for (const repo of repositories) {
+        const [owner, repoName] = repo.full_name.split('/');
+
+        // Check if repository already exists (from PAT setup)
+        const existingRepo = await Repository.findByOwnerAndRepo(
+          owner,
+          repoName
+        );
+
+        if (existingRepo) {
+          // Migrate from PAT to GitHub App
+          await Repository.update(existingRepo._id, {
+            installationId: installation.id,
+            // Keep userId for now during migration
+          });
+          console.log(`Migrated ${owner}/${repoName} to GitHub App`);
+        } else {
+          // Create new repository
+          await Repository.create({
+            owner,
+            repo: repoName,
+            installationId: installation.id,
+            configured: true,
+          });
+          console.log(`Added ${owner}/${repoName} via GitHub App`);
+        }
+      }
+    }
+  } else if (action === 'deleted') {
+    console.log(
+      `GitHub App uninstalled by ${installation.account.login} (ID: ${installation.id})`
+    );
+
+    // Disable repositories for this installation
+    const repos = await Repository.findByInstallationId(installation.id);
+    for (const repo of repos) {
+      await Repository.update(repo._id, {
+        configured: false,
+        installationId: null,
+      });
+      console.log(`Disabled ${repo.owner}/${repo.repo} (app uninstalled)`);
+    }
+  }
+}
+
+/**
+ * Handle GitHub App installation repositories webhook
+ * @param {object} payload
+ */
+export async function handleInstallationRepositoriesWebhook(payload) {
+  const { action, installation, repositories_added, repositories_removed } =
+    payload;
+
+  if (action === 'added') {
+    for (const repo of repositories_added) {
+      const [owner, repoName] = repo.full_name.split('/');
+
+      // Check if repository already exists
+      const existingRepo = await Repository.findByOwnerAndRepo(owner, repoName);
+
+      if (existingRepo) {
+        // Update existing repository to use GitHub App
+        await Repository.update(existingRepo._id, {
+          installationId: installation.id,
+          configured: true,
+        });
+        console.log(`Updated ${owner}/${repoName} to use GitHub App`);
+      } else {
+        // Create new repository
+        await Repository.create({
+          owner,
+          repo: repoName,
+          installationId: installation.id,
+          configured: true,
+        });
+        console.log(`Added ${owner}/${repoName} to installation`);
+      }
+    }
+  } else if (action === 'removed') {
+    for (const repo of repositories_removed) {
+      const [owner, repoName] = repo.full_name.split('/');
+      const existingRepo = await Repository.findByOwnerAndRepo(owner, repoName);
+      if (existingRepo && existingRepo.installationId === installation.id) {
+        await Repository.update(existingRepo._id, {
+          configured: false,
+          installationId: null,
+        });
+        console.log(`Removed ${owner}/${repoName} from installation`);
+      }
+    }
+  }
+}
diff --git a/src/helpers/pullRequestProcessor.js b/src/helpers/pullRequestProcessor.js
index 8cee56d..4fa078b 100644
--- a/src/helpers/pullRequestProcessor.js
+++ b/src/helpers/pullRequestProcessor.js
@@ -10,21 +10,21 @@ import { User, Repository } from '../database/models.js';
 
 /**
  * Set GitHub status for a pull request
- * @param {object} user
+ * @param {object|number} authMethod - User object or installationId
  * @param {string} owner
  * @param {string} repo
  * @param {number} pullNumber
  * @param {object} pullRequestData
  */
 async function setPullRequestStatus(
-  user,
+  authMethod,
   owner,
   repo,
   pullNumber,
   pullRequestData
 ) {
   try {
-    const sha = await getLatestCommitSha(user, owner, repo, pullNumber);
+    const sha = await getLatestCommitSha(authMethod, owner, repo, pullNumber);
     const coefficient = pullRequestData.stats.coefficient;
     const targetUrl = `https://www.worlddriven.org/${owner}/${repo}/pull/${pullNumber}`;
 
@@ -40,7 +40,7 @@ async function setPullRequestStatus(
     }
 
     await setCommitStatus(
-      user,
+      authMethod,
       owner,
       repo,
       sha,
@@ -90,9 +90,29 @@ export async function processPullRequests() {
         `Processing repository: ${repository.owner}/${repository.repo}`
       );
 
-      const user = await User.findById(repository.userId);
-      if (!user) {
-        const error = `No user found for repository ${repository.owner}/${repository.repo}`;
+      let authMethod;
+
+      // Determine authentication method
+      if (repository.installationId) {
+        // Use GitHub App
+        authMethod = repository.installationId;
+        console.log(
+          `Using GitHub App authentication (installation: ${repository.installationId})`
+        );
+      } else if (repository.userId) {
+        // Use PAT (legacy)
+        const user = await User.findById(repository.userId);
+        if (!user) {
+          const error = `No user found for repository ${repository.owner}/${repository.repo}`;
+          console.log(error);
+          repoResult.errors.push(error);
+          results.errors++;
+          continue;
+        }
+        authMethod = user;
+        console.log(`Using PAT authentication (user: ${user._id})`);
+      } else {
+        const error = `No authentication method configured for ${repository.owner}/${repository.repo}`;
         console.log(error);
         repoResult.errors.push(error);
         results.errors++;
@@ -101,7 +121,7 @@ export async function processPullRequests() {
 
       try {
         const pullRequests = await getPullRequests(
-          user,
+          authMethod,
           repository.owner,
           repository.repo
         );
@@ -122,7 +142,7 @@ export async function processPullRequests() {
 
           try {
             const pullRequestData = await getPullRequestData(
-              user,
+              authMethod,
               repository.owner,
               repository.repo,
               pullRequest.number
@@ -133,7 +153,7 @@ export async function processPullRequests() {
 
             // Set GitHub status for this pull request
             await setPullRequestStatus(
-              user,
+              authMethod,
               repository.owner,
               repository.repo,
               pullRequest.number,
@@ -146,7 +166,7 @@ export async function processPullRequests() {
               );
 
               const mergeResponse = await mergePullRequest(
-                user,
+                authMethod,
                 repository.owner,
                 repository.repo,
                 pullRequest.number
@@ -156,7 +176,7 @@ export async function processPullRequests() {
                 const comment =
                   'This pull request was merged by [worlddriven](https://www.worlddriven.org).';
                 await createIssueComment(
-                  user,
+                  authMethod,
                   repository.owner,
                   repository.repo,
                   pullRequest.number,
diff --git a/src/index.js b/src/index.js
index c876029..1c81433 100644
--- a/src/index.js
+++ b/src/index.js
@@ -20,6 +20,10 @@ import {
   handlePullRequestReviewWebhook,
   handlePushWebhook,
 } from './helpers/webhookHandler.js';
+import {
+  handleInstallationWebhook,
+  handleInstallationRepositoriesWebhook,
+} from './helpers/installationHandler.js';
 
 const mongoSessionStore = MongoStore.create({
   clientPromise: client.connect(),
@@ -85,6 +89,13 @@ async function startServer() {
     res.sendFile('./static/privacyPolicy.html', { root: '.' });
   });
 
+  app.get('/install-app', function (req, res) {
+    // Redirect to GitHub App installation page
+    const appName = process.env.GITHUB_APP_NAME || 'world-driven';
+    const installUrl = `https://github.com/apps/${appName}/installations/new`;
+    res.redirect(installUrl);
+  });
+
   app.get('/login', function (req, res) {
     if (req.session.userId) {
       res.redirect('/dashboard');
@@ -322,6 +333,14 @@ async function startServer() {
       let result;
 
       switch (eventType) {
+        case 'installation':
+          result = await handleInstallationWebhook(data);
+          break;
+
+        case 'installation_repositories':
+          result = await handleInstallationRepositoriesWebhook(data);
+          break;
+
         case 'pull_request':
           result = await handlePullRequestWebhook(data);
           break;