#[account(zero_copy)] (Anchor)

An Anchor attribute applied to account structs to enable zero-copy deserialization, where account data is accessed directly from the underlying byte buffer using repr(C) memory layout rather than Borsh deserialization. Zero-copy accounts use AccountLoader instead of Account and are accessed via load() or load_mut(). Best for large accounts where full deserialization would consume excessive compute units. Fields must be fixed-size types (no Vec, String, or Option).