WebSocket 1000 Normal Closure vs 1003 Unsupported Data
Both WebSocket 1000 (Normal Closure) and 1003 (Unsupported Data) belong to the WebSocket Close Codes category. 1000 indicates that the connection has been closed cleanly, meaning the purpose for which it was established has been fulfilled. Both endpoints agree the session is complete. Meanwhile, 1003 means that an endpoint received a type of data it cannot accept. For example, a text-only endpoint received a binary message, or vice versa.
Description
The connection has been closed cleanly, meaning the purpose for which it was established has been fulfilled. Both endpoints agree the session is complete.
Quand vous le voyez
The WebSocket connection closed gracefully after both sides finished exchanging data. This is the expected close code for a successful session.
Comment résoudre
No fix needed — this indicates everything worked as intended. If you did not expect the connection to close, check your application logic for premature close() calls.
Description
An endpoint received a type of data it cannot accept. For example, a text-only endpoint received a binary message, or vice versa.
Quand vous le voyez
The client sent a binary frame to a server that only handles text, or a text frame to a binary-only endpoint. The receiver does not know how to process this data type.
Comment résoudre
Verify the message type (text vs binary) matches what the server expects. Update your client to send the correct opcode for the data format.
Différences clés
WebSocket 1000: The connection has been closed cleanly, meaning the purpose for which it was established has been fulfilled. Both endpoints agree the session is complete.
WebSocket 1003: An endpoint received a type of data it cannot accept. For example, a text-only endpoint received a binary message, or vice versa.
You encounter 1000 when the WebSocket connection closed gracefully after both sides finished exchanging data. This is the expected close code for a successful session.
You encounter 1003 when the client sent a binary frame to a server that only handles text, or a text frame to a binary-only endpoint. The receiver does not know how to process this data type.
Quand utiliser lequel
For 1000 (Normal Closure): No fix needed — this indicates everything worked as intended. If you did not expect the connection to close, check your application logic for premature close() calls. For 1003 (Unsupported Data): Verify the message type (text vs binary) matches what the server expects. Update your client to send the correct opcode for the data format.