A simple reference for overlapping HTTP/WS close codes
IANA Websocket Close Code Registry
| Category | HTTP Status Code | HTTP Status Text | WebSocket Close Code | WebSocket Close Text | Description |
|---|---|---|---|---|---|
| Success/Normal Closure | 200 | OK | 1000 | Normal Closure | The request was successfully processed, or the connection was closed normally. |
| No Status/No Response Received | 204 | No Content | 1005 | No Status Received | No additional information is provided, or no status was received. |
| Protocol Error/Bad Request | 400 | Bad Request | 1002 | Protocol Error | The request contained malformed syntax or protocol violations. |
| Invalid Data/Bad Request | 400 | Bad Request | 1007 | Invalid Frame Payload Data | The server detected invalid data (e.g., invalid encoding) in the request or payload. |
| Unauthorized Access | 401 | Unauthorized | 3000 | Unauthorized | The client attempted an unauthorized action. |
| Policy Violation/Forbidden | 403 | Forbidden | 1008 | Policy Violation | The request violated server policies, or access was forbidden. |
| Unsupported Media Type/Unsupported Data | 415 | Unsupported Media Type | 1003 | Unsupported Data | The client sent data that is not supported by the server. |
| Payload Too Large/Message Too Big | 413 | Payload Too Large | 1009 | Message Too Big | The message/request size exceeds server limits. |
| Unsupported Extension/Required Extensions Not Met | 426 | Upgrade Required | 1010 | Mandatory Extension | The client expected a specific protocol extension that was not agreed upon. |
| Bad Gateway/Gateway Timeout | 502 | Bad Gateway | 1014 | Bad Gateway | The server received an invalid response from an upstream server. |
| Service Unavailable/Service Restart | 503 | Service Unavailable | 1012 | Service Restart | The server is restarting, causing the connection to terminate. |
| Service Unavailable/Try Again Later | 503 | Service Unavailable | 1013 | Try Again Later | The server is currently overloaded; client should try again later. |
| Handshake Error/TLS Required | 426 | Upgrade Required | 1015 | TLS Handshake | The client attempted to connect without the required TLS handshake or protocol. |
| Internal Server Error | 500 | Internal Server Error | 1006 | Abnormal Closure | The connection closed unexpectedly, likely due to an internal server error. |
| Internal Server Error | 500 | Internal Server Error | 1011 | Internal Error | The server encountered an unexpected condition, leading to an error. |
| Custom/Private Codes | - | - | 4000-4999 | Reserved for Private Use | Both HTTP and WebSocket provide ranges for application-specific, non-standard error handling. |