diff --git a/server/middleware/multi-tenant-auth.js b/server/middleware/multi-tenant-auth.js
index 0d55cec..0c18ee7 100644
--- a/server/middleware/multi-tenant-auth.js
+++ b/server/middleware/multi-tenant-auth.js
@@ -279,6 +279,33 @@ class MultiTenantAuth {
       { expiresIn: '24h' }
     );
   }
+
+  /**
+   * Determine tenant from request (slug or subdomain)
+   */
+  async determineTenant(req) {
+    try {
+      // Try to get tenant from subdomain first
+      const host = req.get('host') || '';
+      const subdomain = host.split('.')[0];
+      
+      // If subdomain is not localhost/IP, use it as tenant slug
+      if (subdomain && !subdomain.match(/^(localhost|127\.0\.0\.1|\d+\.\d+\.\d+\.\d+)$/)) {
+        return subdomain;
+      }
+      
+      // Fallback: get from user's tenant if authenticated
+      if (req.user && req.user.tenant_id) {
+        const tenant = await Tenant.findByPk(req.user.tenant_id);
+        return tenant ? tenant.slug : null;
+      }
+      
+      return null;
+    } catch (error) {
+      console.error('Error determining tenant:', error);
+      return null;
+    }
+  }
 }
 
 module.exports = MultiTenantAuth;
diff --git a/server/routes/alert.js b/server/routes/alert.js
index 1c95dce..e4a79cf 100644
--- a/server/routes/alert.js
+++ b/server/routes/alert.js
@@ -35,12 +35,20 @@ router.get('/rules', authenticateToken, async (req, res) => {
     
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
@@ -53,7 +61,7 @@ router.get('/rules', authenticateToken, async (req, res) => {
       include: [{
         model: User,
         as: 'user',
-        where: { tenant_id: tenantId },
+        where: { tenant_id: tenant.id },
         attributes: ['id', 'username', 'email']
       }],
       limit: Math.min(parseInt(limit), 100),
@@ -126,12 +134,20 @@ router.put('/rules/:id', authenticateToken, validateRequest(alertRuleSchema), as
   try {
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
@@ -142,7 +158,7 @@ router.put('/rules/:id', authenticateToken, validateRequest(alertRuleSchema), as
       include: [{
         model: User,
         as: 'user',
-        where: { tenant_id: tenantId },
+        where: { tenant_id: tenant.id },
         attributes: ['id']
       }]
     });
@@ -177,12 +193,20 @@ router.delete('/rules/:id', authenticateToken, async (req, res) => {
   try {
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
@@ -193,7 +217,7 @@ router.delete('/rules/:id', authenticateToken, async (req, res) => {
       include: [{
         model: User,
         as: 'user',
-        where: { tenant_id: tenantId },
+        where: { tenant_id: tenant.id },
         attributes: ['id']
       }]
     });
@@ -236,12 +260,20 @@ router.get('/logs', authenticateToken, async (req, res) => {
     
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
     
@@ -263,7 +295,7 @@ router.get('/logs', authenticateToken, async (req, res) => {
         include: [{
           model: User,
           as: 'user',
-          where: { tenant_id: tenantId },
+          where: { tenant_id: tenant.id },
           attributes: ['id', 'username']
         }],
         attributes: ['id', 'name', 'priority']
@@ -302,12 +334,20 @@ router.get('/stats', authenticateToken, async (req, res) => {
 
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
@@ -316,7 +356,7 @@ router.get('/stats', authenticateToken, async (req, res) => {
       include: [{
         model: User,
         as: 'user',
-        where: { tenant_id: tenantId },
+        where: { tenant_id: tenant.id },
         attributes: []
       }],
       attributes: ['id']
diff --git a/server/routes/dashboard.js b/server/routes/dashboard.js
index 87f99b5..a26e536 100644
--- a/server/routes/dashboard.js
+++ b/server/routes/dashboard.js
@@ -14,17 +14,25 @@ router.get('/overview', authenticateToken, async (req, res) => {
 
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
     // Create base filter for tenant devices
-    const tenantDeviceFilter = { tenant_id: tenantId };
+    const tenantDeviceFilter = { tenant_id: tenant.id };
 
     // Get basic statistics - filtered by tenant
     const [
@@ -39,6 +47,7 @@ router.get('/overview', authenticateToken, async (req, res) => {
       DroneDetection.count({ 
         include: [{
           model: Device,
+          as: 'device',
           where: tenantDeviceFilter,
           attributes: []
         }],
@@ -47,6 +56,7 @@ router.get('/overview', authenticateToken, async (req, res) => {
       DroneDetection.count({
         include: [{
           model: Device,
+          as: 'device',
           where: tenantDeviceFilter,
           attributes: []
         }],
@@ -58,6 +68,7 @@ router.get('/overview', authenticateToken, async (req, res) => {
       DroneDetection.count({
         include: [{
           model: Device,
+          as: 'device',
           where: tenantDeviceFilter,
           attributes: []
         }],
@@ -145,12 +156,20 @@ router.get('/activity', authenticateToken, async (req, res) => {
 
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
@@ -163,7 +182,7 @@ router.get('/activity', authenticateToken, async (req, res) => {
       include: [{
         model: Device,
         as: 'device',
-        where: { tenant_id: tenantId },
+        where: { tenant_id: tenant.id },
         attributes: ['id', 'name', 'geo_lat', 'geo_lon', 'location_description']
       }],
       limit: Math.min(parseInt(limit), 200),
@@ -176,7 +195,7 @@ router.get('/activity', authenticateToken, async (req, res) => {
       include: [{
         model: Device,
         as: 'device',
-        where: { tenant_id: tenantId },
+        where: { tenant_id: tenant.id },
         attributes: ['id', 'name', 'geo_lat', 'geo_lon']
       }],
       limit: Math.min(parseInt(limit), 50),
@@ -239,12 +258,20 @@ router.get('/charts/detections', authenticateToken, async (req, res) => {
 
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
@@ -266,7 +293,8 @@ router.get('/charts/detections', authenticateToken, async (req, res) => {
     const detectionCounts = await DroneDetection.findAll({
       include: [{
         model: Device,
-        where: { tenant_id: tenantId },
+        as: 'device',
+        where: { tenant_id: tenant.id },
         attributes: []
       }],
       where: { 
@@ -308,12 +336,20 @@ router.get('/charts/devices', authenticateToken, async (req, res) => {
 
     // Initialize multi-tenant auth to determine tenant
     const multiTenantAuth = new MultiTenantAuth();
-    const tenantId = await multiTenantAuth.determineTenant(req);
+    const tenantSlug = await multiTenantAuth.determineTenant(req);
     
-    if (!tenantId) {
-      return res.status(403).json({
+    if (!tenantSlug) {
+      return res.status(400).json({
         success: false,
-        message: 'Access denied: No tenant context'
+        message: 'Unable to determine tenant'
+      });
+    }
+
+    const tenant = await Tenant.findOne({ where: { slug: tenantSlug } });
+    if (!tenant) {
+      return res.status(404).json({
+        success: false,
+        message: 'Tenant not found'
       });
     }
 
@@ -329,7 +365,7 @@ router.get('/charts/devices', authenticateToken, async (req, res) => {
       include: [{
         model: Device,
         as: 'device',
-        where: { tenant_id: tenantId },
+        where: { tenant_id: tenant.id },
         attributes: ['name', 'location_description']
       }],
       group: ['device_id', 'device.id', 'device.name', 'device.location_description'],