Anchor is a development framework for building smart contracts (programs) on the Solana blockchain. Anchor provides a structured, opinionated approach to Solana program development that reduces boilerplate code and makes programs easier to audit and verify.

Anchor smart contracts are written in Rust and compiled to Solana's BPF bytecode. They use a declarative account structure that makes it clear which accounts a program reads and writes, improving security and auditability.

Most professional DeFi protocols on Solana — including token lockers, staking pools, and DEXs — are built using Anchor. The framework's structured approach makes programs easier to audit for security vulnerabilities.