# WebSocket Options Configure options for connections that use WebSocket. ## Topics ### Creating WebSocket Connections [`nw_protocol_copy_ws_definition()`](/documentation/Network/nw_protocol_copy_ws_definition()) Accesses the system definition of the WebSocket protocol. [`nw_ws_create_options(_:)`](/documentation/Network/nw_ws_create_options(_:)) Initializes a default set of WebSocket connection options. [`nw_ws_version_t`](/documentation/Network/nw_ws_version_t) Supported versions of the WebSocket protocol. [`nw_ws_options_set_auto_reply_ping(_:_:)`](/documentation/Network/nw_ws_options_set_auto_reply_ping(_:_:)) Configures the connection to automatically reply to Ping messages instead of delivering them to you. [`nw_ws_options_set_maximum_message_size(_:_:)`](/documentation/Network/nw_ws_options_set_maximum_message_size(_:_:)) Sets the maximum allowed message size, in bytes, to be received by the WebSocket connection. ### Configuring Client Handshakes [`nw_ws_options_add_additional_header(_:_:_:)`](/documentation/Network/nw_ws_options_add_additional_header(_:_:_:)) Adds additional HTTP header fields to be sent by the client during the WebSocket handshake. [`nw_ws_options_add_subprotocol(_:_:)`](/documentation/Network/nw_ws_options_add_subprotocol(_:_:)) Adds to the list of supported application protocols that will be presented to a WebSocket server during connection establishment. [`nw_ws_options_set_skip_handshake(_:_:)`](/documentation/Network/nw_ws_options_set_skip_handshake(_:_:)) Specifies whether the WebSocket protocol skips its handshake and begins framing data once the underlying connection is established. ### Handling WebSocket Messages [`nw_protocol_metadata_is_ws(_:)`](/documentation/Network/nw_protocol_metadata_is_ws(_:)) Checks whether a metadata object represents a WebSocket message. [`nw_ws_create_metadata(_:)`](/documentation/Network/nw_ws_create_metadata(_:)) Initializes a WebSocket message with a specific type code. [`nw_ws_metadata_get_opcode(_:)`](/documentation/Network/nw_ws_metadata_get_opcode(_:)) Checks the type code on a WebSocket message. [`nw_ws_opcode_t`](/documentation/Network/nw_ws_opcode_t) Types of messages that you send and receive on a WebSocket connection. [`nw_ws_metadata_set_close_code(_:_:)`](/documentation/Network/nw_ws_metadata_set_close_code(_:_:)) Sets a close code on a WebSocket message. [`nw_ws_metadata_get_close_code(_:)`](/documentation/Network/nw_ws_metadata_get_close_code(_:)) Accesses the close code on a WebSocket message. [`nw_ws_close_code_t`](/documentation/Network/nw_ws_close_code_t) Types of codes used upon closing a WebSocket connection. [`nw_ws_metadata_set_pong_handler(_:_:_:)`](/documentation/Network/nw_ws_metadata_set_pong_handler(_:_:_:)) Sets a handler on a Ping message to be invoked when the corresponding Pong message is received. [`nw_ws_pong_handler_t`](/documentation/Network/nw_ws_pong_handler_t) A handler that indicates that a Pong message has been received for a previously sent Ping message, or that an error was encountered. [`nw_ws_metadata_copy_server_response(_:)`](/documentation/Network/nw_ws_metadata_copy_server_response(_:)) Accesses the WebSocket server’s response sent during the handshake. ### Handling Server Handshakes [`nw_ws_options_set_client_request_handler(_:_:_:)`](/documentation/Network/nw_ws_options_set_client_request_handler(_:_:_:)) Sets a handler to react to as a server to inbound WebSocket client handshakes. [`nw_ws_client_request_handler_t`](/documentation/Network/nw_ws_client_request_handler_t) A handler that delivers inbound client handshake requests. [`nw_ws_request_t`](/documentation/Network/nw_ws_request_t) A WebSocket handshake request sent from a client to a server. [`nw_ws_request_enumerate_subprotocols(_:_:)`](/documentation/Network/nw_ws_request_enumerate_subprotocols(_:_:)) Enumerates the supported subprotocols in a WebSocket message. [`nw_ws_subprotocol_enumerator_t`](/documentation/Network/nw_ws_subprotocol_enumerator_t) A block that enumerates the supported subprotocols in a WebSocket client request. [`nw_ws_request_enumerate_additional_headers(_:_:)`](/documentation/Network/nw_ws_request_enumerate_additional_headers(_:_:)) Enumerates additional HTTP headers in a WebSocket message. [`nw_ws_additional_header_enumerator_t`](/documentation/Network/nw_ws_additional_header_enumerator_t) A block that enumerates additional HTTP headers in a WebSocket client request. [`nw_ws_response_t`](/documentation/Network/nw_ws_response_t) A WebSocket handshake reponse sent from a server to a client. [`nw_ws_response_create(_:_:)`](/documentation/Network/nw_ws_response_create(_:_:)) Initializes a WebSocket server response with a status and selected subprotocol. [`nw_ws_response_status_t`](/documentation/Network/nw_ws_response_status_t) Status values that are sent with a WebSocket server response. [`nw_ws_response_add_additional_header(_:_:_:)`](/documentation/Network/nw_ws_response_add_additional_header(_:_:_:)) Adds an additional HTTP header to a WebSocket server response. [`nw_ws_response_get_status(_:)`](/documentation/Network/nw_ws_response_get_status(_:)) Accesses the status of a WebSocket server response. [`nw_ws_response_get_selected_subprotocol(_:)`](/documentation/Network/nw_ws_response_get_selected_subprotocol(_:)) Accesses the selected subprotocol in a WebSocket server response. [`nw_ws_response_enumerate_additional_headers(_:_:)`](/documentation/Network/nw_ws_response_enumerate_additional_headers(_:_:)) Enumerates the additional HTTP headers in a WebSocket server response. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)