For larger projects, I organize code into multiple crates within a Cargo workspace. The root Cargo.toml lists workspace members, and each crate has its own dependencies and Cargo.toml. This lets you split code into libraries and binaries, share code b

Sqlx is a pure-Rust SQL client that checks queries at compile time against your database schema. The query! macro connects to your DB during compilation and validates that columns and types match. This catches typos and schema drift before runtime. It

Tower is a library of modular middleware (called "layers") for async services. Axum is built on Tower, so you can use any Tower middleware: TimeoutLayer, CompressionLayer, TraceLayer, etc. Layers wrap services, adding behavior like logging, metrics, o

Axum is a modern web framework built on tokio and hyper. It uses extractors (like Json<T>, Path<T>, State<S>) to parse requests into Rust types, and the compiler ensures your handlers match their routes. Middleware is just functions,

Reqwest is the most popular async HTTP client for Rust. It's built on tokio and hyper, with a high-level API for making requests. Connection pooling, redirects, timeouts, and TLS are handled automatically. I use the builder pattern to configure client

Serde is Rust's serialization framework, supporting JSON, YAML, TOML, MessagePack, and more through format-specific crates. With #[derive(Serialize, Deserialize)], your structs automatically convert to and from these formats. Serde is extremely fast b

For CLI tools, clap is the de facto standard. Version 4+ supports derive macros, letting you define arguments as a struct with attributes. The library auto-generates help text, validates inputs, and supports subcommands. I annotate fields with #[arg(s

When you need multiple ownership without threads, Rc<T> (reference counted) is the answer. It tracks the number of owners at runtime and frees the data when the count reaches zero. For mutability, combine it with RefCell<T>, which enforces

Box<T> is Rust's simplest smart pointer: it allocates T on the heap and gives you ownership. When the Box goes out of scope, the heap memory is freed. I use Box when I need indirection (like recursive types), when moving large structs is expensi

Rust's match expression is like a switch statement on steroids. It requires exhaustive handling of all cases, and the compiler enforces this. You can match on enums, tuples, references, ranges, and destructure nested data. Guards (if condition) add ex

Rust's Iterator trait provides a rich set of combinators (.map(), .filter(), .fold(), etc.) that compose without allocating intermediate collections. Iterators are lazy: they don't do work until you consume them with .collect(), .for_each(), or simila

Rust has no null. Instead, Option<T> represents a value that might be absent. It's an enum with two variants: Some(T) and None. You must explicitly handle both cases with match, if let, or combinator methods like .map() and .unwrap_or(). This el