Arion Proxy

The fastest programmable gateway for services, models and tools.

Arion Proxy is a high-performance, memory-safe proxy written in Rust. It natively supports the Envoy configuration model and the commonly used Envoy features, and extends them with Arion-native capabilities for AI workloads.

Why Arion

• Memory safe. Implemented in Rust, avoiding entire classes of memory-management and data-race bugs and making Arion a robust and secure foundation for your traffic.
• Envoy-native configuration. Arion's configuration is generated from Envoy's xDS protobuf definitions and is consumed the same way Envoy consumes it — as static bootstrap config or dynamically from an existing xDS control plane. The commonly used Envoy features are supported: routing, load balancing, TLS, JWT authentication, global rate limiting, circuit breaking, connection limits, external processing, health checks, and more — see the example configurations in arion-proxy/conf/.
• Native AI extensions. Alongside Envoy feature parity, Arion adds its own extensions for AI traffic, such as an MCP gateway with RBAC for routing model and tool traffic.
• Programmable. HTTP filters can be written in WebAssembly and loaded at runtime. The Wasm SDK lives in this repo (arion-wasm-sdk).
• Observable. Prometheus metrics, distributed tracing, and access logging.

Quick start

Build from source

git clone https://github.com/arion-gateway/arion
cd arion
git submodule update --init --force
cargo build

Run

cargo run --bin arion -- --config arion-proxy/conf/arion-runtime.yaml

arion-proxy/conf/ contains further example configurations (JWT, rate limiting, circuit breaking, health checks, and more).

Docker

# Build
docker build -t arion-proxy -f docker/Dockerfile .

# Run
docker run -p 8000:8000 --name arion-proxy arion-proxy

# Verify
curl -v http://localhost:8000/direct-response   # HTTP 200 with "meow! 🐱"

See docker/README.md for detailed Docker options, including testing load balancing against real backends.

Cargo features

Optional features of the arion-proxy crate (enable with --features <name>):

Feature	Description
wasm	HTTP Wasm filter host (Wasmtime). Required to load Wasm HTTP filters at runtime.
metrics	Metrics collection
prometheus	Prometheus metrics export (implies metrics)
access-log	Access logging
tracing	Distributed tracing
config-dump	Admin config dump support
jemalloc	Use jemalloc as the allocator
instrumentation	Internal instrumentation
dhat-heap	Heap profiling with dhat

Example:

cargo build -p arion-proxy --features wasm

Runtime configuration

To control how many CPU cores/threads Arion uses, set the ARION_CPU_LIMIT environment variable. This is especially useful in containerized environments where access to /sys/fs is restricted; Arion uses the value to size its worker thread pool.

Documentation

See docs/ for guides, including metrics, tracing, access logging, global rate limiting, the MCP gateway, and demos.

License

Arion Proxy is licensed under the Apache License, Version 2.0.