Rail introduces a self-hosting systems language with zero C dependencies, featuring a garbage collector written entirely in ARM64 assembly. The 4,687-line compiler produces a 729 KB binary that compiles itself to byte-identical output, with no libc or runtime C code required. This approach eliminates transitive dependencies, creating a minimal binary that needs only as + ld + the kernel to function.

Version 3.0.0 adds pure-Rail TLS 1.3 implementation with full X.509 chain validation, enabling HTTPS connections without OpenSSL or curl. The language now supports connections to Anthropic's API through a simple import statement, validating certificate chains end-to-end to macOS's trust store. Four backends are supported: ARM64 macOS, Linux ARM64, Linux x86_64, and WASM.

The language combines practical functionality with theoretical innovation. Its self-compiling nature creates a unique feedback loop where the compiler itself serves as the fitness function for training AI models. The production surface remains intentionally narrow, shipping only NIST- or RFC-validated crypto primitives including ChaCha20-Poly1305, x25519, and ECDSA-P256/P-384.

This implementation demonstrates how systems programming can achieve both security and minimalism through careful architectural decisions. The ARM64 assembly components ensure predictable performance without compromising the language's purity.