The server returns some response headers before final HTTP message.
What does HTTP 103 mean?
The 103 Early Hints code is part of the 1XX class. This is an informational response — the server received the request and the client should continue or wait.
When is it used?
A server returns 103 Early Hints in situations matching the definition above. You will encounter it inspecting network requests, reading logs, or testing an API. Whether it signals a problem depends on its class: 2xx and 3xx are normal, while 4xx and 5xx usually need attention on the client or server respectively.