Quick Start
RelayCore is a high-performance Rust traffic interception engine. This guide will help you get up and running in under 5 minutes.
Installation
Choose your preferred installation method:
Cargo (Recommended)
cargo install relay-core-clinpm
npm install -g @relay-core/cliPre-built Binaries
Download the latest release from GitHub Releases.
Examples below use relay-core. npm install -g @relay-core/cli installs that command; Cargo installs a file named relay-core-cli.
Generate CA Certificate
For HTTPS interception, generate a CA first (default: ~/.relay-core/):
relay-core ca generateCheck status:
relay-core ca statusInstall to the system trust store:
# macOS (recommended)
relay-core ca install
# Linux (Debian/Ubuntu example)
sudo cp ~/.relay-core/ca_cert.pem /usr/local/share/ca-certificates/relay-core.crt
sudo update-ca-certificates
# Windows
# Import ~/.relay-core/ca_cert.pem via certmgr.mscStart the Proxy
# Background: daemon + proxy (idempotent)
relay-core start
# Foreground: same daemon, with the TUI attached
relay-core run --ui
# Foreground: same daemon, with the Web UI (open the URL from status)
relay-core run --web
# A different proxy port, or the whole status at a glance
relay-core start --listen 127.0.0.1:9090
relay-core statusOne background daemon owns the engine: it holds the state, serves the control API, the Web UI and the MCP endpoint, and survives the terminal that started it. The proxy listens on 127.0.0.1:8080 by default; relay-core status prints the ports actually in use, and relay-core stop stops the proxy while keeping the daemon and its history. Captured history defaults to at most 5000 flows or 7 days (tune with policy retention). An MCP client (@relay-core/mcp) attaches to that same daemon — it may autostart the daemon, then use proxy_start for the proxy.
Configure Your Client
Point your HTTP client to RelayCore:
# curl
curl --proxy http://localhost:8080 https://example.com
# Environment variables
export HTTP_PROXY=http://localhost:8080
export HTTPS_PROXY=http://localhost:8080