ArcBox is an open-source, Rust-based container and virtual machine runtime designed for macOS, serving as a high-performance alternative to Docker Desktop and OrbStack. Developed from scratch, the runtime implements its own Virtual Machine Monitor (VMM) using Hypervisor.framework and a Swift shim for Virtualization.framework, alongside custom VirtIO implementations for networking, storage, and console. It supports four distinct workload tiers: drop-in Docker-compatible containers (including native Kubernetes via k3s), disposable microVMs for AI agents powered by Firecracker, full Linux machines, and ephemeral macOS guests utilizing APFS copy-on-write cloning. For Apple Silicon users, it enables running linux/amd64 images via FEX emulation and provides high-speed filesystem sharing through VirtioFS/FUSE and an NFSv4 export via vsock relay. Performance benchmarks target a cold boot time of under 1.5 seconds and a single-stream host-to-VM network throughput of 22.7 Gbps, which is approximately double Apple's standard VirtIO-net performance. The platform also includes a CLI (`abctl`) and a native SwiftUI desktop application that communicates with a background daemon via gRPC. ArcBox is currently in public beta under MIT/Apache-2.0 licenses.