Server-Sent Events (SSE) is a standard that allows browser clients to receive a stream of updates from a server over an HTTP connection. To support SSE with Kong Gateway, configure a Service and Route to handle HTTP requests passing through Kong Gateway.
When proxying SSE connections, ensure the request does not exceed the configured proxy read timeout; otherwise, Kong Gateway will terminate the upstream connection. You can adjust this setting with the Service entity’s read_timeout property (there is no field literally named upstream_read_timeout). For more details, see the Service object reference documentation.
Buffering can cause issues with SSE. To prevent this, do not disable proxy buffering globally using Nginx directives. Instead, have your upstream service send the X-Accel-Buffering: no response header for SSE connections. This explicitly disables buffering for those responses when proxied through Kong Gateway.