diff --git a/src-tauri/src/extension/permissions/check.rs b/src-tauri/src/extension/permissions/check.rs
new file mode 100644
index 0000000..afaca06
--- /dev/null
+++ b/src-tauri/src/extension/permissions/check.rs
@@ -0,0 +1,64 @@
+// src-tauri/src/extension/permissions/commands.rs
+
+use crate::extension::error::ExtensionError;
+use crate::extension::permissions::manager::PermissionManager;
+use crate::AppState;
+use tauri::State;
+
+#[tauri::command]
+pub async fn check_web_permission(
+    extension_id: String,
+    method: String,
+    url: String,
+    state: State<'_, AppState>,
+) -> Result<(), ExtensionError> {
+    PermissionManager::check_web_permission(&state, &extension_id, &method, &url).await
+}
+
+#[tauri::command]
+pub async fn check_database_permission(
+    extension_id: String,
+    resource: String,
+    operation: String,
+    state: State<'_, AppState>,
+) -> Result<(), ExtensionError> {
+    let action = match operation.as_str() {
+        "read" => crate::extension::permissions::types::Action::Database(
+            crate::extension::permissions::types::DbAction::Read,
+        ),
+        "write" => crate::extension::permissions::types::Action::Database(
+            crate::extension::permissions::types::DbAction::ReadWrite,
+        ),
+        _ => {
+            return Err(ExtensionError::ValidationError {
+                reason: format!("Invalid database operation: {}", operation),
+            })
+        }
+    };
+
+    PermissionManager::check_database_permission(&state, &extension_id, action, &resource).await
+}
+
+#[tauri::command]
+pub async fn check_filesystem_permission(
+    extension_id: String,
+    path: String,
+    operation: String,
+    state: State<'_, AppState>,
+) -> Result<(), ExtensionError> {
+    let action = match operation.as_str() {
+        "read" => crate::extension::permissions::types::Action::Filesystem(
+            crate::extension::permissions::types::FsAction::Read,
+        ),
+        "write" => crate::extension::permissions::types::Action::Filesystem(
+            crate::extension::permissions::types::FsAction::ReadWrite,
+        ),
+        _ => {
+            return Err(ExtensionError::ValidationError {
+                reason: format!("Invalid filesystem operation: {}", operation),
+            })
+        }
+    };
+
+    PermissionManager::check_filesystem_permission(&state, &extension_id, action, &path).await
+}
diff --git a/src-tauri/src/extension/permissions/mod.rs b/src-tauri/src/extension/permissions/mod.rs
index 740af61..b49306a 100644
--- a/src-tauri/src/extension/permissions/mod.rs
+++ b/src-tauri/src/extension/permissions/mod.rs
@@ -1,3 +1,4 @@
+pub mod check;
 pub mod manager;
 pub mod types;
 pub mod validator;
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index 6002597..1e0399e 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -1,7 +1,14 @@
 mod crdt;
 mod database;
 mod extension;
-use crate::{crdt::hlc::HlcService, database::DbConnection, extension::core::ExtensionManager};
+use crate::{
+    crdt::hlc::HlcService,
+    database::DbConnection,
+    extension::{
+        core::ExtensionManager,
+        webview::ExtensionWebviewManager,
+    }
+};
 use std::sync::{Arc, Mutex};
 use tauri::Manager;
 
@@ -9,10 +16,15 @@ pub mod table_names {
     include!(concat!(env!("OUT_DIR"), "/tableNames.rs"));
 }
 
+pub mod event_names {
+    include!(concat!(env!("OUT_DIR"), "/eventNames.rs"));
+}
+
 pub struct AppState {
     pub db: DbConnection,
     pub hlc: Mutex<HlcService>,
     pub extension_manager: ExtensionManager,
+    pub extension_webview_manager: ExtensionWebviewManager,
 }
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
@@ -54,6 +66,7 @@ pub fn run() {
             db: DbConnection(Arc::new(Mutex::new(None))),
             hlc: Mutex::new(HlcService::new()),
             extension_manager: ExtensionManager::new(),
+            extension_webview_manager: ExtensionWebviewManager::new(),
         })
         //.manage(ExtensionState::default())
         .plugin(tauri_plugin_dialog::init())
@@ -80,6 +93,9 @@ pub fn run() {
             extension::database::extension_sql_select,
             extension::web::extension_web_fetch,
             extension::web::extension_web_open,
+            extension::permissions::check::check_web_permission,
+            extension::permissions::check::check_database_permission,
+            extension::permissions::check::check_filesystem_permission,
             extension::get_all_dev_extensions,
             extension::get_all_extensions,
             extension::get_extension_info,
@@ -89,6 +105,11 @@ pub fn run() {
             extension::preview_extension,
             extension::remove_dev_extension,
             extension::remove_extension,
+            extension::open_extension_webview_window,
+            extension::close_extension_webview_window,
+            extension::focus_extension_webview_window,
+            extension::update_extension_webview_window_position,
+            extension::update_extension_webview_window_size,
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");
diff --git a/src/composables/handlers/permissions.ts b/src/composables/handlers/permissions.ts
index ec68c4b..bdecf1c 100644
--- a/src/composables/handlers/permissions.ts
+++ b/src/composables/handlers/permissions.ts
@@ -1,5 +1,6 @@
 import type { IHaexHubExtension } from '~/types/haexhub'
 import type { ExtensionRequest } from './types'
+import { invoke } from '@tauri-apps/api/core'
 
 export async function handlePermissionsMethodAsync(
   request: ExtensionRequest,
@@ -9,6 +10,102 @@ export async function handlePermissionsMethodAsync(
     throw new Error('Extension not found')
   }
 
-  // TODO: Implementiere Permission Request UI
-  throw new Error('Permission methods not yet implemented')
+  const { method, params } = request
+
+  if (method === 'permissions.web.check') {
+    return await checkWebPermissionAsync(params, extension)
+  }
+
+  if (method === 'permissions.database.check') {
+    return await checkDatabasePermissionAsync(params, extension)
+  }
+
+  if (method === 'permissions.filesystem.check') {
+    return await checkFilesystemPermissionAsync(params, extension)
+  }
+
+  throw new Error(`Unknown permission method: ${method}`)
+}
+
+async function checkWebPermissionAsync(
+  params: Record<string, unknown>,
+  extension: IHaexHubExtension,
+) {
+  const url = params.url as string
+  const method = (params.method as string) || 'GET'
+
+  if (!url) {
+    throw new Error('URL is required')
+  }
+
+  try {
+    await invoke<void>('check_web_permission', {
+      extensionId: extension.id,
+      method,
+      url,
+    })
+
+    return { status: 'granted' }
+  } catch (error: any) {
+    // Permission denied errors return a specific error code
+    if (error?.code === 1002 || error?.message?.includes('Permission denied')) {
+      return { status: 'denied' }
+    }
+    // Other errors should be thrown
+    throw error
+  }
+}
+
+async function checkDatabasePermissionAsync(
+  params: Record<string, unknown>,
+  extension: IHaexHubExtension,
+) {
+  const resource = params.resource as string
+  const operation = params.operation as string
+
+  if (!resource || !operation) {
+    throw new Error('Resource and operation are required')
+  }
+
+  try {
+    await invoke<void>('check_database_permission', {
+      extensionId: extension.id,
+      resource,
+      operation,
+    })
+
+    return { status: 'granted' }
+  } catch (error: any) {
+    if (error?.code === 1002 || error?.message?.includes('Permission denied')) {
+      return { status: 'denied' }
+    }
+    throw error
+  }
+}
+
+async function checkFilesystemPermissionAsync(
+  params: Record<string, unknown>,
+  extension: IHaexHubExtension,
+) {
+  const path = params.path as string
+  const operation = params.operation as string
+
+  if (!path || !operation) {
+    throw new Error('Path and operation are required')
+  }
+
+  try {
+    await invoke<void>('check_filesystem_permission', {
+      extensionId: extension.id,
+      path,
+      operation,
+    })
+
+    return { status: 'granted' }
+  } catch (error: any) {
+    if (error?.code === 1002 || error?.message?.includes('Permission denied')) {
+      return { status: 'denied' }
+    }
+    throw error
+  }
 }
diff --git a/src/composables/handlers/web.ts b/src/composables/handlers/web.ts
index e6d9ea8..83c76e8 100644
--- a/src/composables/handlers/web.ts
+++ b/src/composables/handlers/web.ts
@@ -62,11 +62,23 @@ async function handleWebFetchAsync(
       body: response.body,
       url: response.url,
     }
-  } catch (error) {
+  } catch (error: any) {
+    console.error('Web request error:', error)
+
+    // Check if it's a permission denied error
+    if (error?.code === 1002 || error?.message?.includes('Permission denied')) {
+      const toast = useToast()
+      toast.add({
+        title: 'Permission denied',
+        description: `Extension "${extension.name}" does not have permission to access ${url}`,
+        color: 'error',
+      })
+    }
+
     if (error instanceof Error) {
       throw new Error(`Web request failed: ${error.message}`)
     }
-    throw new Error('Web request failed with unknown error')
+    throw new Error(`Web request failed with unknown error: ${JSON.stringify(error)}`)
   }
 }