diff --git a/cmd/server/main.go b/cmd/server/main.go
index 8e97f53..cff6057 100644
--- a/cmd/server/main.go
+++ b/cmd/server/main.go
@@ -62,7 +62,7 @@ func main() {
 
 	// Initialize services
 	appService := services.NewApplicationService(appRepo, logger)
-	tokenService := services.NewTokenService(tokenRepo, appRepo, permRepo, grantRepo, cfg.GetString("INTERNAL_HMAC_KEY"), logger)
+	tokenService := services.NewTokenService(tokenRepo, appRepo, permRepo, grantRepo, cfg.GetString("INTERNAL_HMAC_KEY"), cfg, logger)
 	authService := services.NewAuthenticationService(cfg, logger)
 
 	// Initialize handlers
diff --git a/internal/services/token_service.go b/internal/services/token_service.go
index 197f933..2378431 100644
--- a/internal/services/token_service.go
+++ b/internal/services/token_service.go
@@ -8,6 +8,8 @@ import (
 	"github.com/google/uuid"
 	"go.uber.org/zap"
 
+	"github.com/kms/api-key-service/internal/auth"
+	"github.com/kms/api-key-service/internal/config"
 	"github.com/kms/api-key-service/internal/crypto"
 	"github.com/kms/api-key-service/internal/domain"
 	"github.com/kms/api-key-service/internal/repository"
@@ -20,6 +22,7 @@ type tokenService struct {
 	permRepo      repository.PermissionRepository
 	grantRepo     repository.GrantedPermissionRepository
 	tokenGen      *crypto.TokenGenerator
+	jwtManager    *auth.JWTManager
 	logger        *zap.Logger
 }
 
@@ -30,15 +33,17 @@ func NewTokenService(
 	permRepo repository.PermissionRepository,
 	grantRepo repository.GrantedPermissionRepository,
 	hmacKey string,
+	config config.ConfigProvider,
 	logger *zap.Logger,
 ) TokenService {
 	return &tokenService{
-		tokenRepo: tokenRepo,
-		appRepo:   appRepo,
-		permRepo:  permRepo,
-		grantRepo: grantRepo,
-		tokenGen:  crypto.NewTokenGenerator(hmacKey),
-		logger:    logger,
+		tokenRepo:  tokenRepo,
+		appRepo:    appRepo,
+		permRepo:   permRepo,
+		grantRepo:  grantRepo,
+		tokenGen:   crypto.NewTokenGenerator(hmacKey),
+		jwtManager: auth.NewJWTManager(config, logger),
+		logger:     logger,
 	}
 }
 
@@ -197,11 +202,57 @@ func (s *tokenService) Delete(ctx context.Context, tokenID uuid.UUID, userID str
 func (s *tokenService) GenerateUserToken(ctx context.Context, appID, userID string, permissions []string) (string, error) {
 	s.logger.Info("Generating user token", zap.String("app_id", appID), zap.String("user_id", userID))
 
-	// TODO: Validate application
-	// TODO: Validate permissions
-	// TODO: Generate JWT token
+	// Validate application exists
+	app, err := s.appRepo.GetByID(ctx, appID)
+	if err != nil {
+		s.logger.Error("Failed to get application", zap.Error(err), zap.String("app_id", appID))
+		return "", fmt.Errorf("application not found: %w", err)
+	}
 
-	return "user-token-placeholder-" + userID, nil
+	// Validate permissions exist (if any provided)
+	var validPermissions []string
+	if len(permissions) > 0 {
+		validPermissions, err = s.permRepo.ValidatePermissionScopes(ctx, permissions)
+		if err != nil {
+			s.logger.Error("Failed to validate permissions", zap.Error(err))
+			return "", fmt.Errorf("failed to validate permissions: %w", err)
+		}
+
+		if len(validPermissions) != len(permissions) {
+			s.logger.Warn("Some permissions are invalid", 
+				zap.Strings("requested", permissions),
+				zap.Strings("valid", validPermissions))
+			return "", fmt.Errorf("some requested permissions are invalid")
+		}
+	}
+
+	// Create user token with proper timing
+	now := time.Now()
+	userToken := &domain.UserToken{
+		AppID:       appID,
+		UserID:      userID,
+		Permissions: validPermissions,
+		IssuedAt:    now,
+		ExpiresAt:   now.Add(app.TokenRenewalDuration.Duration),
+		MaxValidAt:  now.Add(app.MaxTokenDuration.Duration),
+		TokenType:   domain.TokenTypeUser,
+	}
+
+	// Generate JWT token using JWT manager
+	tokenString, err := s.jwtManager.GenerateToken(userToken)
+	if err != nil {
+		s.logger.Error("Failed to generate JWT token", zap.Error(err))
+		return "", fmt.Errorf("failed to generate token: %w", err)
+	}
+
+	s.logger.Info("User token generated successfully", 
+		zap.String("app_id", appID),
+		zap.String("user_id", userID),
+		zap.Strings("permissions", validPermissions),
+		zap.Time("expires_at", userToken.ExpiresAt),
+		zap.Time("max_valid_at", userToken.MaxValidAt))
+
+	return tokenString, nil
 }
 
 // VerifyToken verifies a token and returns verification response
@@ -338,12 +389,101 @@ func (s *tokenService) verifyStaticToken(ctx context.Context, req *domain.Verify
 func (s *tokenService) verifyUserToken(ctx context.Context, req *domain.VerifyRequest, app *domain.Application) (*domain.VerifyResponse, error) {
 	s.logger.Debug("Verifying user token", zap.String("app_id", req.AppID))
 
-	// TODO: Implement JWT token verification
-	// For now, return an error since user tokens are not fully implemented
+	// Check if token is revoked first
+	isRevoked, err := s.jwtManager.IsTokenRevoked(req.Token)
+	if err != nil {
+		s.logger.Error("Failed to check token revocation status", zap.Error(err))
+		return &domain.VerifyResponse{
+			Valid:     false,
+			Permitted: false,
+			Error:     "Token verification failed",
+		}, nil
+	}
+
+	if isRevoked {
+		s.logger.Warn("Token is revoked", zap.String("app_id", req.AppID))
+		return &domain.VerifyResponse{
+			Valid:     false,
+			Permitted: false,
+			Error:     "Token has been revoked",
+		}, nil
+	}
+
+	// Validate JWT token
+	claims, err := s.jwtManager.ValidateToken(req.Token)
+	if err != nil {
+		s.logger.Warn("JWT token validation failed", zap.Error(err), zap.String("app_id", req.AppID))
+		return &domain.VerifyResponse{
+			Valid:     false,
+			Permitted: false,
+			Error:     "Invalid token",
+		}, nil
+	}
+
+	// Verify the token is for the correct application
+	if claims.AppID != req.AppID {
+		s.logger.Warn("Token app_id mismatch", 
+			zap.String("expected", req.AppID),
+			zap.String("actual", claims.AppID))
+		return &domain.VerifyResponse{
+			Valid:     false,
+			Permitted: false,
+			Error:     "Token not valid for this application",
+		}, nil
+	}
+
+	// Check specific permissions if requested
+	var permissionResults map[string]bool
+	var permitted bool = true // Default to true if no specific permissions requested
+	
+	if len(req.Permissions) > 0 {
+		permissionResults = make(map[string]bool)
+		
+		// Check each requested permission against token permissions
+		for _, requestedPerm := range req.Permissions {
+			hasPermission := false
+			for _, tokenPerm := range claims.Permissions {
+				if tokenPerm == requestedPerm {
+					hasPermission = true
+					break
+				}
+			}
+			permissionResults[requestedPerm] = hasPermission
+			
+			// If any permission is missing, set permitted to false
+			if !hasPermission {
+				permitted = false
+			}
+		}
+	}
+
+	// Convert timestamps
+	var expiresAt, maxValidAt *time.Time
+	if claims.ExpiresAt != nil {
+		expTime := claims.ExpiresAt.Time
+		expiresAt = &expTime
+	}
+	if claims.MaxValidAt > 0 {
+		maxTime := time.Unix(claims.MaxValidAt, 0)
+		maxValidAt = &maxTime
+	}
+
+	s.logger.Info("User token verified successfully", 
+		zap.String("user_id", claims.UserID),
+		zap.String("app_id", req.AppID),
+		zap.Strings("permissions", claims.Permissions),
+		zap.Bool("permitted", permitted))
+
 	return &domain.VerifyResponse{
-		Valid:     false,
-		Permitted: false,
-		Error:     "User token verification not yet implemented",
+		Valid:             true,
+		Permitted:         permitted,
+		UserID:            claims.UserID,
+		Permissions:       claims.Permissions,
+		PermissionResults: permissionResults,
+		ExpiresAt:         expiresAt,
+		MaxValidAt:        maxValidAt,
+		TokenType:         domain.TokenTypeUser,
+		Claims:            claims.Claims,
 	}, nil
 }
 
diff --git a/kms-frontend/src/App.tsx b/kms-frontend/src/App.tsx
index 3e693f1..8f84ab5 100644
--- a/kms-frontend/src/App.tsx
+++ b/kms-frontend/src/App.tsx
@@ -8,6 +8,7 @@ import {
   UserOutlined,
   AuditOutlined,
   LoginOutlined,
+  ExperimentOutlined,
 } from '@ant-design/icons';
 import { useState } from 'react';
 import './App.css';
@@ -19,6 +20,8 @@ import Tokens from './components/Tokens';
 import Users from './components/Users';
 import Audit from './components/Audit';
 import Login from './components/Login';
+import TokenTester from './components/TokenTester';
+import TokenTesterCallback from './components/TokenTesterCallback';
 import { AuthProvider, useAuth } from './contexts/AuthContext';
 
 const { Header, Sider, Content } = Layout;
@@ -50,6 +53,11 @@ const AppContent: React.FC = () => {
       icon: <KeyOutlined />,
       label: 'Tokens',
     },
+    {
+      key: '/token-tester',
+      icon: <ExperimentOutlined />,
+      label: 'Token Tester',
+    },
     {
       key: '/users',
       icon: <UserOutlined />,
@@ -103,6 +111,8 @@ const AppContent: React.FC = () => {
             <Route path="/" element={<Dashboard />} />
             <Route path="/applications" element={<Applications />} />
             <Route path="/tokens" element={<Tokens />} />
+            <Route path="/token-tester" element={<TokenTester />} />
+            <Route path="/token-tester/callback" element={<TokenTesterCallback />} />
             <Route path="/users" element={<Users />} />
             <Route path="/audit" element={<Audit />} />
             <Route path="*" element={<Navigate to="/" replace />} />
diff --git a/kms-frontend/src/components/TokenTester.tsx b/kms-frontend/src/components/TokenTester.tsx
new file mode 100644
index 0000000..d59ca28
--- /dev/null
+++ b/kms-frontend/src/components/TokenTester.tsx
@@ -0,0 +1,568 @@
+import React, { useState, useEffect } from 'react';
+import {
+  Card,
+  Button,
+  Form,
+  Input,
+  Select,
+  Space,
+  Typography,
+  Alert,
+  Divider,
+  Row,
+  Col,
+  Tag,
+  Checkbox,
+  message,
+  Modal,
+  Steps,
+} from 'antd';
+import {
+  PlayCircleOutlined,
+  CheckCircleOutlined,
+  ExclamationCircleOutlined,
+  CopyOutlined,
+  ReloadOutlined,
+  LinkOutlined,
+} from '@ant-design/icons';
+import { apiService, Application } from '../services/apiService';
+
+const { Title, Text, Paragraph } = Typography;
+const { Option } = Select;
+const { TextArea } = Input;
+const { Step } = Steps;
+
+interface LoginTestResult {
+  success: boolean;
+  token?: string;
+  redirectUrl?: string;
+  userId?: string;
+  appId?: string;
+  expiresIn?: number;
+  error?: string;
+  timestamp: string;
+}
+
+interface CallbackTestResult {
+  success: boolean;
+  token?: string;
+  verified?: boolean;
+  permissions?: string[];
+  error?: string;
+  timestamp: string;
+}
+
+const availablePermissions = [
+  'app.read',
+  'app.write',
+  'app.delete',
+  'token.read',
+  'token.create',
+  'token.revoke',
+  'repo.read',
+  'repo.write',
+  'repo.admin',
+  'permission.read',
+  'permission.write',
+  'permission.grant',
+  'permission.revoke',
+];
+
+const TokenTester: React.FC = () => {
+  const [applications, setApplications] = useState<Application[]>([]);
+  const [loading, setLoading] = useState(false);
+  const [testLoading, setTestLoading] = useState(false);
+  const [callbackLoading, setCallbackLoading] = useState(false);
+  const [loginResult, setLoginResult] = useState<LoginTestResult | null>(null);
+  const [callbackResult, setCallbackResult] = useState<CallbackTestResult | null>(null);
+  const [currentStep, setCurrentStep] = useState(0);
+  const [callbackModalVisible, setCallbackModalVisible] = useState(false);
+  const [form] = Form.useForm();
+  const [callbackForm] = Form.useForm();
+
+  useEffect(() => {
+    loadApplications();
+  }, []);
+
+  const loadApplications = async () => {
+    try {
+      setLoading(true);
+      const response = await apiService.getApplications();
+      setApplications(response.data);
+    } catch (error) {
+      console.error('Failed to load applications:', error);
+      message.error('Failed to load applications');
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  const handleLoginTest = async (values: any) => {
+    try {
+      setTestLoading(true);
+      setCurrentStep(1);
+      
+      const selectedApp = applications.find(app => app.app_id === values.app_id);
+      const callbackUrl = `${window.location.origin}/token-tester/callback`;
+      
+      // Store test data in localStorage for the callback page
+      const testData = {
+        app_id: values.app_id,
+        permissions: values.permissions || [],
+        use_callback: values.use_callback,
+        timestamp: new Date().toISOString(),
+      };
+      localStorage.setItem('token_tester_data', JSON.stringify(testData));
+      
+      console.log('Testing login flow with:', {
+        app_id: values.app_id,
+        permissions: values.permissions || [],
+        redirect_uri: values.use_callback ? callbackUrl : undefined,
+      });
+
+      const response = await apiService.login(
+        values.app_id,
+        values.permissions || [],
+        values.use_callback ? callbackUrl : undefined
+      );
+
+      console.log('Login response:', response);
+
+      const result: LoginTestResult = {
+        success: true,
+        token: response.token,
+        redirectUrl: response.redirect_url,
+        userId: response.user_id,
+        appId: values.app_id,
+        expiresIn: response.expires_in,
+        timestamp: new Date().toISOString(),
+      };
+
+      setLoginResult(result);
+      setCurrentStep(2);
+      
+      message.success('Login test completed successfully!');
+
+      // If we have a redirect URL, show the callback modal
+      if (response.redirect_url && values.use_callback) {
+        setCallbackModalVisible(true);
+        // Pre-fill the callback form with the token from the redirect URL
+        const urlParams = new URLSearchParams(response.redirect_url.split('?')[1]);
+        const token = urlParams.get('token');
+        if (token) {
+          callbackForm.setFieldsValue({
+            app_id: values.app_id,
+            token: token,
+            permissions: values.permissions || [],
+          });
+        }
+      }
+
+    } catch (error: any) {
+      console.error('Login test failed:', error);
+      
+      const result: LoginTestResult = {
+        success: false,
+        error: error.response?.data?.message || error.message || 'Login test failed',
+        timestamp: new Date().toISOString(),
+      };
+      
+      setLoginResult(result);
+      setCurrentStep(2);
+      message.error('Login test failed');
+    } finally {
+      setTestLoading(false);
+    }
+  };
+
+  const handleCallbackTest = async (values: any) => {
+    try {
+      setCallbackLoading(true);
+      setCurrentStep(3);
+
+      console.log('Testing callback with token verification:', values);
+
+      // Verify the token received in the callback
+      const verifyResponse = await apiService.verifyToken({
+        app_id: values.app_id,
+        type: 'user',
+        token: values.token,
+        permissions: values.permissions || [],
+      });
+
+      console.log('Token verification response:', verifyResponse);
+
+      const result: CallbackTestResult = {
+        success: verifyResponse.valid,
+        token: values.token,
+        verified: verifyResponse.valid,
+        permissions: verifyResponse.permissions,
+        error: verifyResponse.error,
+        timestamp: new Date().toISOString(),
+      };
+
+      setCallbackResult(result);
+      setCurrentStep(4);
+      
+      if (verifyResponse.valid) {
+        message.success('Callback test completed successfully!');
+      } else {
+        message.warning('Callback test completed - token verification failed');
+      }
+
+    } catch (error: any) {
+      console.error('Callback test failed:', error);
+      
+      const result: CallbackTestResult = {
+        success: false,
+        error: error.response?.data?.message || error.message || 'Callback test failed',
+        timestamp: new Date().toISOString(),
+      };
+      
+      setCallbackResult(result);
+      setCurrentStep(4);
+      message.error('Callback test failed');
+    } finally {
+      setCallbackLoading(false);
+    }
+  };
+
+  const resetTest = () => {
+    setCurrentStep(0);
+    setLoginResult(null);
+    setCallbackResult(null);
+    setCallbackModalVisible(false);
+    form.resetFields();
+    callbackForm.resetFields();
+    // Clear stored test data
+    localStorage.removeItem('token_tester_data');
+  };
+
+  const copyToClipboard = (text: string) => {
+    navigator.clipboard.writeText(text);
+    message.success('Copied to clipboard');
+  };
+
+  const openCallbackUrl = () => {
+    if (loginResult?.redirectUrl) {
+      window.open(loginResult.redirectUrl, '_blank');
+    }
+  };
+
+  return (
+    <div>
+      <Space direction="vertical" size="large" style={{ width: '100%' }}>
+        <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
+          <div>
+            <Title level={2}>Token Tester</Title>
+            <Text type="secondary">
+              Test the /login flow and callback handling for user tokens
+            </Text>
+          </div>
+          <Button
+            icon={<ReloadOutlined />}
+            onClick={resetTest}
+            disabled={testLoading || callbackLoading}
+          >
+            Reset Test
+          </Button>
+        </div>
+
+        {/* Test Progress */}
+        <Card title="Test Progress">
+          <Steps current={currentStep} size="small">
+            <Step title="Configure" description="Set up test parameters" />
+            <Step title="Login Test" description="Test /login endpoint" />
+            <Step title="Results" description="Review login results" />
+            <Step title="Callback Test" description="Test callback handling" />
+            <Step title="Complete" description="Test completed" />
+          </Steps>
+        </Card>
+
+        {/* Test Configuration */}
+        <Card title="Test Configuration">
+          <Form
+            form={form}
+            layout="vertical"
+            onFinish={handleLoginTest}
+          >
+            <Row gutter={16}>
+              <Col span={12}>
+                <Form.Item
+                  name="app_id"
+                  label="Application"
+                  rules={[{ required: true, message: 'Please select an application' }]}
+                >
+                  <Select 
+                    placeholder="Select application to test"
+                    loading={loading}
+                  >
+                    {applications.map(app => (
+                      <Option key={app.app_id} value={app.app_id}>
+                        <div>
+                          <Text strong>{app.app_id}</Text>
+                          <br />
+                          <Text type="secondary" style={{ fontSize: '12px' }}>
+                            {app.app_link}
+                          </Text>
+                        </div>
+                      </Option>
+                    ))}
+                  </Select>
+                </Form.Item>
+              </Col>
+              <Col span={12}>
+                <Form.Item
+                  name="use_callback"
+                  valuePropName="checked"
+                  label=" "
+                >
+                  <Checkbox>Use callback URL (test full flow)</Checkbox>
+                </Form.Item>
+              </Col>
+            </Row>
+
+            <Form.Item
+              name="permissions"
+              label="Permissions to Request"
+            >
+              <Checkbox.Group>
+                <Row>
+                  {availablePermissions.map(permission => (
+                    <Col span={8} key={permission} style={{ marginBottom: '8px' }}>
+                      <Checkbox value={permission}>{permission}</Checkbox>
+                    </Col>
+                  ))}
+                </Row>
+              </Checkbox.Group>
+            </Form.Item>
+
+            <Form.Item>
+              <Button
+                type="primary"
+                htmlType="submit"
+                icon={<PlayCircleOutlined />}
+                loading={testLoading}
+                size="large"
+              >
+                Start Login Test
+              </Button>
+            </Form.Item>
+          </Form>
+        </Card>
+
+        {/* Login Test Results */}
+        {loginResult && (
+          <Card 
+            title={
+              <Space>
+                {loginResult.success ? (
+                  <CheckCircleOutlined style={{ color: '#52c41a' }} />
+                ) : (
+                  <ExclamationCircleOutlined style={{ color: '#ff4d4f' }} />
+                )}
+                Login Test Results
+              </Space>
+            }
+          >
+            <Space direction="vertical" size="middle" style={{ width: '100%' }}>
+              <Alert
+                message={loginResult.success ? 'Login Test Successful' : 'Login Test Failed'}
+                description={loginResult.success 
+                  ? 'The /login endpoint responded successfully'
+                  : loginResult.error
+                }
+                type={loginResult.success ? 'success' : 'error'}
+                showIcon
+              />
+
+              {loginResult.success && (
+                <div>
+                  <Row gutter={16}>
+                    {loginResult.token && (
+                      <Col span={12}>
+                        <Card size="small" title="User Token">
+                          <Space direction="vertical" style={{ width: '100%' }}>
+                            <TextArea
+                              value={loginResult.token}
+                              readOnly
+                              rows={3}
+                              style={{ fontFamily: 'monospace', fontSize: '12px' }}
+                            />
+                            <Button
+                              size="small"
+                              icon={<CopyOutlined />}
+                              onClick={() => copyToClipboard(loginResult.token!)}
+                            >
+                              Copy Token
+                            </Button>
+                          </Space>
+                        </Card>
+                      </Col>
+                    )}
+                    
+                    {loginResult.redirectUrl && (
+                      <Col span={12}>
+                        <Card size="small" title="Redirect URL">
+                          <Space direction="vertical" style={{ width: '100%' }}>
+                            <Text code style={{ fontSize: '12px', wordBreak: 'break-all' }}>
+                              {loginResult.redirectUrl}
+                            </Text>
+                            <Space>
+                              <Button
+                                size="small"
+                                icon={<CopyOutlined />}
+                                onClick={() => copyToClipboard(loginResult.redirectUrl!)}
+                              >
+                                Copy URL
+                              </Button>
+                              <Button
+                                size="small"
+                                icon={<LinkOutlined />}
+                                onClick={openCallbackUrl}
+                              >
+                                Open URL
+                              </Button>
+                            </Space>
+                          </Space>
+                        </Card>
+                      </Col>
+                    )}
+                  </Row>
+
+                  <Divider />
+
+                  <Row gutter={16}>
+                    <Col span={6}>
+                      <Text strong>User ID:</Text>
+                      <div>{loginResult.userId || 'N/A'}</div>
+                    </Col>
+                    <Col span={6}>
+                      <Text strong>App ID:</Text>
+                      <div>{loginResult.appId}</div>
+                    </Col>
+                    <Col span={6}>
+                      <Text strong>Expires In:</Text>
+                      <div>{loginResult.expiresIn ? `${loginResult.expiresIn}s` : 'N/A'}</div>
+                    </Col>
+                    <Col span={6}>
+                      <Text strong>Timestamp:</Text>
+                      <div>{new Date(loginResult.timestamp).toLocaleString()}</div>
+                    </Col>
+                  </Row>
+                </div>
+              )}
+            </Space>
+          </Card>
+        )}
+
+        {/* Callback Test Results */}
+        {callbackResult && (
+          <Card 
+            title={
+              <Space>
+                {callbackResult.success ? (
+                  <CheckCircleOutlined style={{ color: '#52c41a' }} />
+                ) : (
+                  <ExclamationCircleOutlined style={{ color: '#ff4d4f' }} />
+                )}
+                Callback Test Results
+              </Space>
+            }
+          >
+            <Space direction="vertical" size="middle" style={{ width: '100%' }}>
+              <Alert
+                message={callbackResult.success ? 'Callback Test Successful' : 'Callback Test Failed'}
+                description={callbackResult.success 
+                  ? 'Token verification in callback was successful'
+                  : callbackResult.error
+                }
+                type={callbackResult.success ? 'success' : 'error'}
+                showIcon
+              />
+
+              {callbackResult.success && callbackResult.permissions && (
+                <div>
+                  <Text strong>Verified Permissions:</Text>
+                  <div style={{ marginTop: '8px' }}>
+                    {callbackResult.permissions.map(permission => (
+                      <Tag key={permission} color="green" style={{ margin: '2px' }}>
+                        {permission}
+                      </Tag>
+                    ))}
+                  </div>
+                </div>
+              )}
+
+              <div>
+                <Text strong>Timestamp:</Text>
+                <div>{new Date(callbackResult.timestamp).toLocaleString()}</div>
+              </div>
+            </Space>
+          </Card>
+        )}
+      </Space>
+
+      {/* Callback Test Modal */}
+      <Modal
+        title="Test Callback Handling"
+        open={callbackModalVisible}
+        onCancel={() => setCallbackModalVisible(false)}
+        onOk={() => callbackForm.submit()}
+        confirmLoading={callbackLoading}
+        width={700}
+      >
+        <Space direction="vertical" size="large" style={{ width: '100%' }}>
+          <Alert
+            message="Callback URL Received"
+            description="The login flow returned a redirect URL with a token. Test the callback handling by verifying the token."
+            type="info"
+            showIcon
+          />
+
+          <Form
+            form={callbackForm}
+            layout="vertical"
+            onFinish={handleCallbackTest}
+          >
+            <Form.Item
+              name="app_id"
+              label="Application ID"
+            >
+              <Input readOnly />
+            </Form.Item>
+
+            <Form.Item
+              name="token"
+              label="Token from Callback"
+              rules={[{ required: true, message: 'Token is required' }]}
+            >
+              <TextArea
+                rows={3}
+                style={{ fontFamily: 'monospace' }}
+                placeholder="Token extracted from callback URL"
+              />
+            </Form.Item>
+
+            <Form.Item
+              name="permissions"
+              label="Permissions to Verify"
+            >
+              <Checkbox.Group disabled>
+                <Row>
+                  {availablePermissions.map(permission => (
+                    <Col span={8} key={permission} style={{ marginBottom: '8px' }}>
+                      <Checkbox value={permission}>{permission}</Checkbox>
+                    </Col>
+                  ))}
+                </Row>
+              </Checkbox.Group>
+            </Form.Item>
+          </Form>
+        </Space>
+      </Modal>
+    </div>
+  );
+};
+
+export default TokenTester;
diff --git a/kms-frontend/src/components/TokenTesterCallback.tsx b/kms-frontend/src/components/TokenTesterCallback.tsx
new file mode 100644
index 0000000..2ebfd40
--- /dev/null
+++ b/kms-frontend/src/components/TokenTesterCallback.tsx
@@ -0,0 +1,379 @@
+import React, { useEffect, useState } from 'react';
+import { useLocation, useNavigate } from 'react-router-dom';
+import {
+  Card,
+  Button,
+  Space,
+  Typography,
+  Alert,
+  Row,
+  Col,
+  Tag,
+  Spin,
+  Result,
+  Input,
+} from 'antd';
+import {
+  CheckCircleOutlined,
+  ExclamationCircleOutlined,
+  CopyOutlined,
+  ArrowLeftOutlined,
+} from '@ant-design/icons';
+import { apiService } from '../services/apiService';
+
+const { Title, Text } = Typography;
+const { TextArea } = Input;
+
+interface CallbackData {
+  token?: string;
+  state?: string;
+  error?: string;
+  error_description?: string;
+}
+
+interface VerificationResult {
+  valid: boolean;
+  permitted: boolean;
+  user_id?: string;
+  permissions: string[];
+  permission_results?: Record<string, boolean>;
+  expires_at?: string;
+  max_valid_at?: string;
+  token_type: string;
+  claims?: Record<string, string>;
+  error?: string;
+}
+
+const TokenTesterCallback: React.FC = () => {
+  const location = useLocation();
+  const navigate = useNavigate();
+  const [loading, setLoading] = useState(true);
+  const [callbackData, setCallbackData] = useState<CallbackData>({});
+  const [verificationResult, setVerificationResult] = useState<VerificationResult | null>(null);
+  const [verificationError, setVerificationError] = useState<string | null>(null);
+
+  useEffect(() => {
+    parseCallbackData();
+  }, [location]);
+
+  const parseCallbackData = async () => {
+    try {
+      setLoading(true);
+      
+      // Parse URL parameters
+      const urlParams = new URLSearchParams(location.search);
+      const data: CallbackData = {
+        token: urlParams.get('token') || undefined,
+        state: urlParams.get('state') || undefined,
+        error: urlParams.get('error') || undefined,
+        error_description: urlParams.get('error_description') || undefined,
+      };
+
+      setCallbackData(data);
+
+      // If we have a token, try to verify it
+      if (data.token && !data.error) {
+        await verifyToken(data.token);
+      }
+
+    } catch (error) {
+      console.error('Error parsing callback data:', error);
+      setVerificationError('Failed to parse callback data');
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  const verifyToken = async (token: string) => {
+    try {
+      // We need to extract app_id from the state or make a best guess
+      // For now, we'll try to verify without specifying app_id
+      // In a real implementation, the app_id should be included in the state parameter
+      
+      // Try to get app_id from localStorage if it was stored during the test
+      const testData = localStorage.getItem('token_tester_data');
+      let appId = '';
+      
+      if (testData) {
+        try {
+          const parsed = JSON.parse(testData);
+          appId = parsed.app_id || '';
+        } catch (e) {
+          console.warn('Could not parse stored test data');
+        }
+      }
+
+      if (!appId) {
+        // If we don't have app_id, we can't verify the token properly
+        setVerificationError('Cannot verify token: Application ID not found in callback state');
+        return;
+      }
+
+      const verifyRequest = {
+        app_id: appId,
+        type: 'user',
+        token: token,
+        permissions: [], // We'll verify without specific permissions
+      };
+
+      const result = await apiService.verifyToken(verifyRequest);
+      setVerificationResult(result);
+
+    } catch (error: any) {
+      console.error('Token verification failed:', error);
+      setVerificationError(
+        error.response?.data?.message || 
+        error.message || 
+        'Token verification failed'
+      );
+    }
+  };
+
+  const copyToClipboard = (text: string) => {
+    navigator.clipboard.writeText(text);
+  };
+
+  const goBackToTester = () => {
+    navigate('/token-tester');
+  };
+
+  if (loading) {
+    return (
+      <div style={{ 
+        display: 'flex', 
+        justifyContent: 'center', 
+        alignItems: 'center', 
+        minHeight: '400px' 
+      }}>
+        <Spin size="large" />
+        <Text style={{ marginLeft: '16px' }}>Processing callback...</Text>
+      </div>
+    );
+  }
+
+  return (
+    <div>
+      <Space direction="vertical" size="large" style={{ width: '100%' }}>
+        <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
+          <div>
+            <Title level={2}>Token Tester - Callback</Title>
+            <Text type="secondary">
+              Callback page for testing the login flow
+            </Text>
+          </div>
+          <Button
+            icon={<ArrowLeftOutlined />}
+            onClick={goBackToTester}
+          >
+            Back to Tester
+          </Button>
+        </div>
+
+        {/* Callback Status */}
+        <Card title="Callback Status">
+          {callbackData.error ? (
+            <Alert
+              message="Callback Error"
+              description={`${callbackData.error}: ${callbackData.error_description || 'No description provided'}`}
+              type="error"
+              showIcon
+            />
+          ) : callbackData.token ? (
+            <Alert
+              message="Callback Successful"
+              description="Token received successfully from the login flow"
+              type="success"
+              showIcon
+            />
+          ) : (
+            <Alert
+              message="Invalid Callback"
+              description="No token or error information found in callback URL"
+              type="warning"
+              showIcon
+            />
+          )}
+        </Card>
+
+        {/* Token Information */}
+        {callbackData.token && (
+          <Card title="Received Token">
+            <Space direction="vertical" style={{ width: '100%' }}>
+              <div>
+                <Text strong>Token:</Text>
+                <TextArea
+                  value={callbackData.token}
+                  readOnly
+                  rows={4}
+                  style={{ fontFamily: 'monospace', fontSize: '12px', marginTop: '8px' }}
+                />
+                <Button
+                  size="small"
+                  icon={<CopyOutlined />}
+                  onClick={() => copyToClipboard(callbackData.token!)}
+                  style={{ marginTop: '8px' }}
+                >
+                  Copy Token
+                </Button>
+              </div>
+
+              {callbackData.state && (
+                <div>
+                  <Text strong>State:</Text>
+                  <div style={{ marginTop: '4px' }}>
+                    <Text code>{callbackData.state}</Text>
+                  </div>
+                </div>
+              )}
+            </Space>
+          </Card>
+        )}
+
+        {/* Token Verification Results */}
+        {verificationResult && (
+          <Card 
+            title={
+              <Space>
+                {verificationResult.valid ? (
+                  <CheckCircleOutlined style={{ color: '#52c41a' }} />
+                ) : (
+                  <ExclamationCircleOutlined style={{ color: '#ff4d4f' }} />
+                )}
+                Token Verification Results
+              </Space>
+            }
+          >
+            <Space direction="vertical" size="middle" style={{ width: '100%' }}>
+              <Alert
+                message={verificationResult.valid ? 'Token Valid' : 'Token Invalid'}
+                description={verificationResult.valid 
+                  ? 'The token was successfully verified'
+                  : verificationResult.error || 'Token verification failed'
+                }
+                type={verificationResult.valid ? 'success' : 'error'}
+                showIcon
+              />
+
+              {verificationResult.valid && (
+                <div>
+                  <Row gutter={16}>
+                    <Col span={12}>
+                      <Card size="small" title="Token Information">
+                        <Space direction="vertical" style={{ width: '100%' }}>
+                          <div>
+                            <Text strong>Token Type:</Text>
+                            <div>
+                              <Tag color="blue">{verificationResult.token_type.toUpperCase()}</Tag>
+                            </div>
+                          </div>
+                          
+                          {verificationResult.user_id && (
+                            <div>
+                              <Text strong>User ID:</Text>
+                              <div>{verificationResult.user_id}</div>
+                            </div>
+                          )}
+
+                          {verificationResult.expires_at && (
+                            <div>
+                              <Text strong>Expires At:</Text>
+                              <div>{new Date(verificationResult.expires_at).toLocaleString()}</div>
+                            </div>
+                          )}
+
+                          {verificationResult.max_valid_at && (
+                            <div>
+                              <Text strong>Max Valid Until:</Text>
+                              <div>{new Date(verificationResult.max_valid_at).toLocaleString()}</div>
+                            </div>
+                          )}
+                        </Space>
+                      </Card>
+                    </Col>
+
+                    <Col span={12}>
+                      <Card size="small" title="Permissions">
+                        <Space direction="vertical" style={{ width: '100%' }}>
+                          {verificationResult.permissions && verificationResult.permissions.length > 0 ? (
+                            <div>
+                              <Text strong>Available Permissions:</Text>
+                              <div style={{ marginTop: '8px' }}>
+                                {verificationResult.permissions.map(permission => (
+                                  <Tag key={permission} color="green" style={{ margin: '2px' }}>
+                                    {permission}
+                                  </Tag>
+                                ))}
+                              </div>
+                            </div>
+                          ) : (
+                            <Text type="secondary">No permissions available</Text>
+                          )}
+
+                          {verificationResult.permission_results && Object.keys(verificationResult.permission_results).length > 0 && (
+                            <div style={{ marginTop: '16px' }}>
+                              <Text strong>Permission Check Results:</Text>
+                              <div style={{ marginTop: '8px' }}>
+                                {Object.entries(verificationResult.permission_results).map(([permission, granted]) => (
+                                  <div key={permission} style={{ marginBottom: '4px' }}>
+                                    <Tag color={granted ? 'green' : 'red'}>
+                                      {permission}: {granted ? 'GRANTED' : 'DENIED'}
+                                    </Tag>
+                                  </div>
+                                ))}
+                              </div>
+                            </div>
+                          )}
+                        </Space>
+                      </Card>
+                    </Col>
+                  </Row>
+
+                  {verificationResult.claims && Object.keys(verificationResult.claims).length > 0 && (
+                    <Card size="small" title="Token Claims" style={{ marginTop: '16px' }}>
+                      <Row gutter={8}>
+                        {Object.entries(verificationResult.claims).map(([key, value]) => (
+                          <Col span={8} key={key} style={{ marginBottom: '8px' }}>
+                            <Text strong>{key}:</Text>
+                            <div>{value}</div>
+                          </Col>
+                        ))}
+                      </Row>
+                    </Card>
+                  )}
+                </div>
+              )}
+            </Space>
+          </Card>
+        )}
+
+        {/* Verification Error */}
+        {verificationError && (
+          <Card title="Verification Error">
+            <Alert
+              message="Token Verification Failed"
+              description={verificationError}
+              type="error"
+              showIcon
+            />
+          </Card>
+        )}
+
+        {/* No Token or Error */}
+        {!callbackData.token && !callbackData.error && (
+          <Result
+            status="warning"
+            title="Invalid Callback"
+            subTitle="This callback page expects to receive either a token or error information from the login flow."
+            extra={
+              <Button type="primary" onClick={goBackToTester}>
+                Go Back to Token Tester
+              </Button>
+            }
+          />
+        )}
+      </Space>
+    </div>
+  );
+};
+
+export default TokenTesterCallback;
diff --git a/server b/server
index e91a7ec..2702590 100755
Binary files a/server and b/server differ