BPF

Solana programs (smart contracts) are written in Rust, C, or C++, then compiled to BPF (or the newer SBF variant). Validators execute BPF bytecode inside a sandboxed VM with strict compute unit limits.

BPF is derived from a Linux kernel technology originally used for packet filtering. Solana adopted it because BPF is fast, has a small runtime footprint, and can be verified for safety before execution.