Services

services run background components that are neither inbounds nor outbounds: a systemd-resolved replacement, a Shadowsocks server management API, a Tailscale DERP relay, and a few operational helpers. The entry shape is the same flat envelope as everywhere else in the config — type / tag plus the selected type's own fields at the same level.

Envelope

Field	Type	Default	Allowed values	Description
type	string	—	resolved | ssm-api | derp | ccm | ocm | oom-killer	Service type. Selects which option struct the rest of the object is decoded into. Some types only exist in builds carrying their tag — see Notes.
tag	string	—	—	Unique name for this service, used in log lines.

Source: option/service.go:16-20 · pinned at v1.13.15 (3708fa1)

Service types

Type	What it runs
resolved	A drop-in replacement for systemd-resolved: a DNS stub listener (defaults to 127.0.0.53:53) that answers via sing-box DNS. Pairs with the resolved DNS server type.
ssm-api	The Shadowsocks Server Management API — an HTTP endpoint for creating and removing users on a running Shadowsocks inbound.
derp	An embedded Tailscale DERP relay server. See Tailscale.
ccm / ocm / oom-killer	Operational helpers (connection/object management, out-of-memory guard) intended for embedded and mobile deployments.

Minimal example

{
  "services": [
    {
      "type": "resolved",
      "tag": "resolved",
      "listen": "127.0.0.53",
      "listen_port": 53
    }
  ]
}

Notes

• resolved embeds the same ListenOptions as inbounds; when omitted, listen defaults to 127.0.0.53 and listen_port to 53.
• ssm-api takes a servers map (path → Shadowsocks inbound tag) and an optional cache_path.
• Build tags gate availability: derp needs with_tailscale, ccm needs with_ccm, ocm needs with_ocm. resolved, ssm-api and oom-killer are always compiled in.
• An unregistered type fails at startup with "unknown service type".

Cross-core notes

• Xray-core has no service list; the closest analogues are the API and Metrics blocks, which spawn management listeners from dedicated config keys.
• mihomo exposes management through the external controller rather than configurable background services.

Source: option/service.go:16-20 · v1.13.15 (3708fa1)