Rouler brings per-app split tunnelling to Windows
A new Windows tool called Rouler lets developers route traffic from specific applications through different network interfaces at the same time. You can send browser traffic through a privacy VPN while work apps use a corporate tunnel and everything else runs over your normal connection. The beta released recently and runs on 64-bit Intel and AMD systems.
How the custom Rust driver works
Rouler installs a Windows network driver written in Rust. It operates at the network layer and does not replace your VPN clients. WireGuard, Tailscale, Mullvad, OpenVPN and AmneziaWG all keep running normally. Rouler reads the interfaces Windows already exposes and applies rules before the OS makes its routing decision. The driver is small and changes as little of the system networking stack as possible. No virtual adapters, no user-mode proxy, no custom NAT and no hooks that trigger game anti-cheat.
Rules match apps destinations or both
A rule targets an executable or a Windows service, optionally narrowed to a destination IP or subnet. Firefox can use Mullvad for all traffic while Chrome uses Tailscale only for 10.0.0.0/20 and falls back to system routing for everything else. Steam with no rule follows the normal Windows route table. Each interface keeps its own routes so you can run several VPNs together as long as their routes do not conflict. Rouler never edits your route table.
Live view shows every connection outcome
The UI displays a live table of connections showing the application, destination, outcome and which interface carried the packet. Outcomes include diverted, system routed, app chose and blocked. Blocked happens when a rule points to an interface that cannot reach the destination so traffic is dropped instead of leaked. DNS lookups currently bypass app rules because Windows funnels them through a single system service.
Performance numbers from the beta
The installer is 4.3 MB. Memory settles to 15 to 20 MB within 30 seconds minimized to the tray. CPU usage is negligible under normal load. The developer measured full upload speed on a 2.5 Gb/s link and no measurable latency added to games or calls. The driver only works hard under synthetic loads far beyond what real applications generate.
What this means for Windows network tooling
Windows has long lacked a clean way to bind specific processes to specific interfaces without third-party virtual adapters or proxy chains. Rouler fills that gap by sitting between the application and the routing decision. Teams that maintain separate VPNs for production access, staging environments and personal privacy can now run all three without containerizing workloads or juggling routing metrics. The approach also helps developers test cross-region behavior by pointing a single binary at different exits per destination subnet.
Roadmap and current limitations
The project is a solo effort by an independent developer in Australia with 25 years of Windows experience. The roadmap prioritizes driver correctness first then stability across real-world setups then packaged-app and folder rules plus UI polish. No ARM build exists yet. The interface is English only. The beta is free but the release version will be paid with pricing undecided. Feedback goes to beta@rouler.io.