What is Serde and how is it used in Rust?

Serde (SERialization/DEserialization) is Rust's de-facto standard framework for converting Rust data structures to and from formats like JSON, YAML, TOML, MessagePack, and many others. Add serde = { version = "1", features = ["derive"] } and serde_json = "1" to Cargo.toml. Annotate your struct with #[derive(Serialize, Deserialize)]. Serialize to JSON: serde_json::to_string(&my_struct). Deserialize from JSON: serde_json::from_str::<MyStruct>(json_str). Serde uses a zero-copy deserialization strategy and is extremely fast. Field-level attributes like #[serde(rename = "user_name")], #[serde(skip_serializing_if = "Option::is_none")], and #[serde(default)] give precise control over the serialization format.