headers

headers sets, appends or deletes request and response headers.

server:
  http:
    middlewares:
      proxy_headers:
        headers:
          custom_request_headers:
            X-Forwarded-Prefix: /api
          custom_response_headers:
            X-Frame-Options: DENY
            Server: ""
          append_response_headers:
            Vary: Origin

Field	Description
custom_request_headers	Headers set on the request before the next middleware.
custom_response_headers	Headers set on the response.
append_request_headers	Values added to request headers, keeping existing values.
append_response_headers	Values added to response headers, keeping existing values.

Set a header value to an empty string to delete that header.

Response headers are applied when the response starts, so they also replace or delete headers sent by the upstream, such as Server.