XTLS/Xray-core · error

uplinkHTTPMethod can be GET only in packet-up mode

Error message

uplinkHTTPMethod can be GET only in packet-up mode

What it means

SplitHTTPConfig.Build() uppercases the uplink HTTP method (default "POST") and rejects "GET" outside packet-up mode at transport_method.go:374-381. GET requests have no body, so uplink data can only be carried in cookies/headers/URL — which is a packet-up concept. In stream modes the uplink body is required, hence POST.

Source

Thrown at infra/conf/transport_method.go:380

	switch c.UplinkDataPlacement {
	case "":
		c.UplinkDataPlacement = splithttp.PlacementAuto
	case splithttp.PlacementAuto, splithttp.PlacementBody:
	case splithttp.PlacementCookie, splithttp.PlacementHeader:
		if c.Mode != "packet-up" {
			return nil, errors.New("UplinkDataPlacement can be " + c.UplinkDataPlacement + " only in packet-up mode")
		}
	default:
		return nil, errors.New("unsupported uplink data placement: " + c.UplinkDataPlacement)
	}

	if c.UplinkHTTPMethod == "" {
		c.UplinkHTTPMethod = "POST"
	}
	c.UplinkHTTPMethod = strings.ToUpper(c.UplinkHTTPMethod)

	if c.UplinkHTTPMethod == "GET" && c.Mode != "packet-up" {
		return nil, errors.New("uplinkHTTPMethod can be GET only in packet-up mode")
	}

	switch c.SessionIDPlacement {
	case "":
		c.SessionIDPlacement = "path"
	case "path", "cookie", "header", "query":
	default:
		return nil, errors.New("unsupported session placement: " + c.SessionIDPlacement)
	}

	switch c.SeqPlacement {
	case "":
		c.SeqPlacement = "path"
	case "path", "cookie", "header", "query":
	default:
		return nil, errors.New("unsupported seq placement: " + c.SeqPlacement)
	}

View on GitHub (pinned to 7d214f8b09)

Solutions

1. Set "mode": "packet-up" alongside "uplinkHTTPMethod": "GET"
2. Or remove/change uplinkHTTPMethod to "POST" for auto/stream modes

Example fix

// before
"mode": "stream-up", "uplinkHTTPMethod": "GET"
// after
"mode": "packet-up", "uplinkHTTPMethod": "GET"

// Go: GET uplink only in packet-up
m := strings.ToUpper(cfg.UplinkHTTPMethod)
if m == "" {
	m = "POST"
}
mode := cfg.Mode
if mode == "" {
	mode = "auto"
}
if m == "GET" && mode != "packet-up" {
	return errors.New("uplinkHTTPMethod GET requires mode packet-up")
}

When it happens

Trigger: "uplinkHTTPMethod": "get" or "GET" (uppercased at line 377, so any casing matches) combined with mode "auto"/"stream-up"/"stream-one" or mode omitted. Any other method value (PUT, DELETE) is accepted without a mode check.

Common situations: Tuning guides recommending GET-based uplink for CDN compatibility without noting the packet-up requirement; switching mode for troubleshooting and forgetting the method constraint.

Related errors

• unsupported mode:
• UplinkDataPlacement can be only in packet-up mode
• Can not use "downloadSettings" in "stream-one" mode.
• Failed to unmarshal "extra".
• "headers" can't contain "host"

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/d14c4fb3856bead5. Report an issue: GitHub.