Rouler brings per-app and per-IP traffic routing to Windows in free beta

Rouler, a new split-tunnelling utility for Windows, has entered free public beta. Announced through a Show HN post on Hacker News, the tool lets users send traffic from individual apps, or traffic bound for specific IPs and subnets, out of the network interface of their choosing, while running several VPN clients side by side.

What Rouler does

According to the project's website, Rouler operates at the network layer and does one job: directing each app's traffic out of a chosen interface. It bills itself as neither a VPN nor a firewall. A typical setup might send a browser through a privacy VPN, work applications through a corporate tunnel, and everything else over the regular connection, all at the same time.

Because Rouler targets interfaces rather than specific clients, it is not tied to any particular VPN provider. The developer lists WireGuard, Tailscale, Mullvad, OpenVPN and AmneziaWG as compatible, and any interface Windows exposes can be selected by a rule. Rules can match an application, a destination IP or subnet, or both, meaning one app can use different interfaces for different destinations. Rules can also apply to Windows services, so background processes can be pinned to an interface other than the default.

How it works

Rouler ships its own Windows network driver, written in Rust. Rather than rewriting the routing table, it applies rules just before Windows makes its routing decision, and leaves traffic without a rule to normal Windows routing. Each interface's existing routes still determine what it can reach, so multiple interfaces can coexist as long as their routes do not conflict.

The design philosophy is deliberately hands-off. The developer says there are no system hooks, virtual network adapters, user-mode proxies or custom NAT layers, and nothing intended to trip game anti-cheat systems. A live activity view shows every connection, the rule it matched, and whether the traffic was diverted, routed by Windows, or blocked. If a rule's chosen interface cannot carry the traffic, Rouler blocks the connection rather than letting it slip out over another link.

Performance and footprint

The project makes strong performance claims: added latency too small to measure for games and calls, full-speed uploads on a 2.5 Gb/s connection, low CPU use under everyday workloads, a 4.3 MB installer, and roughly 15 to 20 MB of memory once the app settles into the system tray.

Limitations and pricing

The beta has constraints worth noting. It runs on 64-bit Intel and AMD machines only, with no ARM build yet, and the interface is English-only. DNS lookups do not yet follow app rules, because most Windows name resolution passes through a single service that does not identify which application made the request. The installer may trigger a SmartScreen warning until its EV certificate builds reputation with Microsoft, though the developer says the driver itself is signed by Microsoft. Rules for packaged apps and folders are still on the roadmap, behind reliability work.

The beta is free, but the eventual release will not be, and pricing has not been decided. Beta keys are limited in number so the developer can keep up with feedback, and further sign-ups go onto a waitlist. Rouler is a solo project by an independent developer based in Australia, who suggests cautious users try the software in a VM or Windows Sandbox before installing it on a main machine.

Why it matters

Split tunnelling on Windows has historically been awkward: VPN clients either capture all traffic or offer narrow per-client toggles, and running multiple tunnels at once often means manual route-table surgery. Rouler generalises the problem with per-app, per-destination rules spanning any number of interfaces, plus a monitoring view that shows exactly where each connection went. For developers juggling a corporate VPN alongside Tailscale or a privacy tunnel, and for gamers who need anti-cheat-friendly tooling, it addresses a real gap in the Windows networking stack. The open questions are trust and longevity: a brand-new network driver from a solo developer carries inherent risk during beta, and an unannounced paid model may reshape who the tool ends up serving.