sing-box-extended/examples/failover/client.json

{
  "log": {
    "level": "error"
  },
  "dns": {
    "servers": [
      {
        "type": "local",
        "tag": "default"
      }
    ]
  },
  "inbounds": [
    {
      "type": "mixed",
      "tag": "mixed-in",
      "listen_port": 7897
    }
  ],
  "outbounds": [
    {
      "type": "direct",
      "tag": "direct"
    },
    {
      "type": "failover",
      "tag": "failover-out",
      //   - "sequential" (default): try outbounds in order; return the last error
      //     after exhausting them all.
      //   - "cycle":                keep retrying outbounds in round-robin forever
      //     (useful for transient network outages on user devices).
      "strategy": "cycle",
      "delay": "2s", // wait between failed attempts; 0 = no delay
      "outbounds": [
        {
          "type": "vless",
          "tag": "vless-primary",
          "server": "primary.example.com",
          "server_port": 443,
          "uuid": "9b65b7e1-04c8-4717-8f45-2aa61fd25937"
        },
        {
          "type": "trojan",
          "tag": "trojan-secondary",
          "server": "secondary.example.com",
          "server_port": 443,
          "password": "trojan-password"
        },
        {
          "type": "shadowsocks",
          "tag": "ss-tertiary",
          "server": "tertiary.example.com",
          "server_port": 8388,
          "method": "aes-128-gcm",
          "password": "ss-password"
        }
      ]
    }
  ],
  "route": {
    "final": "failover-out",
    "default_domain_resolver": "default",
    "auto_detect_interface": true
  }
}