HTTP/1 responses carry raw bytes, and chunked encoding doesn't affect that (just some packet length prefixing). If you mean binary data would need to be Base64

HTTP/1 responses carry raw bytes, and chunked encoding doesn't affect that (just some packet length prefixing). If you mean binary data would need to be Base64-encoded with server-sent events, that's true. SSE uses text/event-stream as the content type, which is expected to be text. It would be interesting if someone defined a content type for streaming binary events.