The classic panel layout, with the same pages, menus and management script. The difference is that the kernel enforces each data limit, not a program reading a counter every few seconds.
A customer's quota is an nftables quota object on their own address. The packet that crosses it is dropped in the kernel, and the panel is never in the data path.
How it works
WireGuard, and AmneziaWG where DPI blocks plain WireGuard; OpenVPN; L2TP/IPsec, IKEv2 and PPTP for the VPN built into Windows, iPhone, Android and routers; and OpenConnect for the Cisco app. Several tunnels of each on one server.
Tunnels
Other W-UI servers, and 3x-ui and Pasarguard panels, become nodes of this one. You make a customer once and put them on whichever servers you choose.
Nodes
Interfaces, clients, hosts, outbounds, routing, balancers, DNS, the settings tabs, and the w-ui menu numbered 0 to 28, each where you expect it and doing the same thing.
The panel
The installer gets a Let's Encrypt certificate for your domain, or for the server's own IP address, and renews it on its own. The panel starts using the renewed one without a restart.
Certificates
What W-UI does differently
The difference is where the limit is enforced.
Most panels read a byte counter every second or two and cut the customer off once the number passes their quota. Between two readings the customer keeps downloading at full speed: about 25 MB over the quota on a 100 Mbit line, about 250 MB on a gigabit one.
W-UI hands the limit to the kernel as a quota object in nftables. Whatever the line speed, the overshoot is one packet.
bash <(curl -Ls https://raw.githubusercontent.com/AbolfazlTafakori/w-ui/main/install.sh)The installer first asks whether to install manually or automatically. The automatic install asks three questions (the database, a domain, a certificate) and does the rest on its own: the packages and every protocol, kernel forwarding, a check that this server's kernel supports quotas, a service account without root, a hardened systemd unit, the certificate, and the w-ui command. At the end it shows the panel's address, the username and the password.
After the install
When it finishes, the panel is reachable over HTTPS and the w-ui command works on the server. What to do next