Linux

• PreUp = ip route add $endpoint via $gateway
• PostDown = ip route del $endpoint via $gateway
• AllowedIPs 0.0.0.0/1, 128.0.0.0/1 (0.0.0.0/0 works too, wg-quick puts fwmark rule)

MacOS

• PreUp = route add $endpoint $gateway
• PostDown = route delete $endpoint $gateway
• AllowedIPs 0.0.0.0/1, 128.0.0.0/1 (no need for the app)

Windows

• route add $endpoint $gateway
• AllowedIPs 0.0.0.0/1, 128.0.0.0/1
• localhost as WireGuard endpoint won't work. Put the IP address from LAN.

OpenWrt

• ip route add $endpoint via $gateway
• Run tunnel program with "&" on command line
• AllowedIPs 0.0.0.0/1, 128.0.0.0/1

iOS

• route add $endpoint $gateway
• Run tunnel program with "&!" on command line