XUI-Watchdog is a high-performance, open-source quota enforcer daemon for the 3x-ui (Xray-core) ecosystem. It provides robust, native-level enforcement of bandwidth and expiration limits dynamically via the 3x-ui API.

• Zero External Dependencies: A static, single-binary daemon written in Go with negligible resource footprint.
• Smart API-Driven Xray Restart: Instead of using risky OS-level socket killing (ss -K), it detects when the 3x-ui panel disables a user and natively flushes their ghost connections via the /panel/api/server/restartXrayService endpoint.
• Dynamic Rate Limiting: Fully configurable restart cooldown mechanism prevents Xray from entering a restart loop during mass expirations.
• Pre-emptive Sub-second Detection: A threshold-based early warning system. By configuring a high-speed usage threshold (e.g., 0.995 or 99.5%), the daemon can intercept high-bandwidth users before they cross the line, explicitly disabling them via the 3x-ui API between native panel ticks to prevent over-consumption.
• Resilient DB Watcher: Employs fsnotify to track the parent directory (/etc/x-ui/) for database updates and -wal transitions, ensuring the watch isn't dropped during administrative DB restores or backups.
• Offline-First Installer: An interactive bash installation script built for heavily filtered networks, capable of installing local binary payloads without relying on GitHub.

1. Monitor State: XUI-Watchdog monitors /etc/x-ui/ for modifications to the SQLite database.
2. Debounce & Fetch: On DB modification, the daemon safely debounces the event and fetches the live JSON configurations via the /panel/api/inbounds/list API.
3. Threshold Enforcement: A sub-second Goroutine evaluates up + down data limits natively. If a user crosses the configurable threshold, the daemon sends an immediate POST payload directly disabling the user and triggering a cooldown-protected Xray API restart.
4. Native Synchronization: When an admin restores a user's quota, the DB watcher catches the event, resets the user's Enable state in memory, and resets enforcement actions.

To compile XUI-Watchdog for Linux (AMD64), ensure you have Go 1.24+ installed:

# Build the binary
GOOS=linux GOARCH=amd64 go build -o xui-watchdog-linux-amd64 main.go

XUI-Watchdog comes with an interactive, colored installer.

sudo ./install.sh

1. Download or compile the xui-watchdog-linux-amd64 (or xui-watchdog) binary on your local machine.
2. Transfer it to your server using SCP/SFTP to the same directory as install.sh.
3. Run the installer. It will automatically detect the local binary and install it without network fetches!

sudo ./install.sh

The daemon is managed via systemd natively. Log rotation is seamlessly handled via journald to prevent disk exhaustion.

• Check Status: sudo systemctl status xui-watchdog
• View Live Logs: sudo journalctl -u xui-watchdog -f
• Stop Daemon: sudo systemctl stop xui-watchdog
• Start Daemon: sudo systemctl start xui-watchdog

The config file is located at /etc/xui-watchdog/config.json. The installer configures this file interactively, but you can update it if needed.

{
  "panel_url": "http://127.0.0.1:2053",
  "username": "admin",
  "password": "password",
  "db_path": "/etc/x-ui/x-ui.db",
  "check_interval": 0.5,
  "restart_cooldown": 5,
  "threshold": 0.995
}

After modifying the file, simply run sudo ./install.sh and choose Option [1] to rapidly reload your new values.