WebSocket Codes

The WebSocket protocol specification defines codes for closing connections that should be used during client-server communication.

The following table provides details of these codes, as defined in RFC 6455. Codes in bold are deployed by the server.

Code	Meaning	Description
1000	Normal Closure	Indicates normal closure.
1001	Going Away	Indicates that the endpoint is being ended.
1002	Protocol Error	Indicates that the endpoint is closing the connection due to protocol error.
1003	Cannot Accept	Indicates that the connection was ended because the endpoint received a type of data that it cannot be accepted.
1006	Closed Abnormally	Indicates that the connection was ended because an internal error occurred.
1007	Not Consistent	Indicates that the connection was ended because the endpoint received some data that is not consistent with the message type.
1009	Too Big	Indicates that the connection was ended because the endpoint received a type of data that it is too big to be processed.
1011	Unexpected Condition	Indicates that the connection was ended because the server found an unexpected condition.

RFC also defines the usage ranges for the codes:

0-999	Codes in this range are not used.
1000-2999	Reserved for public definition of the protocol, future revisions and extensions.
3000-3999	Reserved for use in libraries, frameworks and applications. These codes are registered directly by IANA (Internet Assigned Numbers Authority).
4000-4999	Reserved for private use and cannot be registered. Codes in this range can be used in common accord by applications.