The Portal uses AJAX for seamless client management without page reloads. All AJAX endpoints require manage_options capability and verify the app_portal_clients_nonce nonce. Handler Method Function app_portal_get_clients POST Retrieve all clients with pagination. Returns client array with metadata. app_portal_get_client POST Retrieve single client by ID. Returns complete client object with all meta fields. app_portal_save_client POST Create or update a client. Accepts POST data with client fields. Auto-sanitizes input. app_portal_delete_client POST Permanently delete a client by ID. Requires client_id in POST data. app_portal_search_clients POST Search clients by name, email, or other criteria. Returns matching clients. app_portal_search_invoices_clients POST Secure AJAX endpoint for