Network Chaos Infrastructure for Developers and Machines
Intercept, delay, drop, and jitter local TCP/UDP packets in real-time. Test how your APIs, WebSockets, and distributed microservices survive spotty subway tunnels and flaky networks with zero proxy overhead.
Built for zero-overhead kernel network manipulation.
WinDivert Interception
Hooks directly into the OS network stack via low-level WinDivert kernel drivers. Intercepts raw IPv4/IPv6 TCP, UDP, and ICMP frames before socket buffering occurs.
Tokio Delay Queues
Asynchronous channel buffers hold delayed packets in user space without thread blocking or OS context-switch overhead.
Target Port Filtering
Target specific local ports (e.g. 3000, 8080, 5000) or individual process IDs so you can stress test your staging service without degrading Spotify or Slack.
Simple CLI installation. Zero config required.
# 1. Install directly with Rust / Cargo
cargo install --git https://github.com/bhavukar/network-relay.git
# 2. Start simulating spotty subway network on port 3000 (Run as Administrator)
subway-sim start --port 3000 --profile subway
# 3. Or pass custom latency and packet drop rates directly
subway-sim start --port 8080 --latency 1500 --drop 15Make your applications resilient against network failure.
Catch race conditions, timeout cascades, and retry loop storms before your users do. 100% Free and Open Source under the MIT License.