# sandbox

Codex CLI is built with Rust, open-sourced under Apache 2.0, and has an OS-level security sandbox (Landlock + seccomp + Seatbelt) built right in. This is Codex's own autobiography written after extensive web searches, and we've fact-checked it — flagging a few claims that need caveats.

Deno's hosted sandbox swaps your real API keys with placeholders inside the sandbox, only revealing the real keys at the proxy layer