Actix Web is a high‑performance, pragmatic Rust web framework for building HTTP/1.x and HTTP/2 servers and clients. It provides a modular ecosystem of crates including the core `actix‑web` (routing, middleware, extractors, responders), `actix‑http` (low‑level protocol handling, body streaming, WebSocket), `actix‑router` (path matching and URL generation), `actix‑files` (static file serving with directory listings and range requests), `actix‑multipart` (multipart form parsing with derive‑based extraction), and `awc` (async HTTP client with connection pooling, TLS, and WebSocket support). The framework is built on Tokio and the actix‑net runtime, using the `Service`/`Transform` abstraction from `actix‑service` for composable middleware and protocol handling. Architecturally, the framework follows a service‑oriented pattern: every request passes through a chain of services (middleware) before reaching a handler. Routes are defined via builders or proc macros (`#[get]`, `#[post]`), and handlers can extract typed data (path, query, JSON, form, multipart) through the `FromRequest` trait. Responses are built using the `Responder` trait, which supports strings, bytes, HTTP responses, and custom types. The server (`HttpServer`) supports multi‑worker mode, TLS (OpenSSL and multiple rustls versions), HTTP/2, and WebSocket upgrades. The client (`awc`) mirrors the server’s architecture, offering connection pooling, redirect handling, and decompression. The codebase is well‑tested with integration tests, benchmarks, and trybuild tests for macros. It exhibits strong engineering practices: builder patterns, trait‑based abstractions, async state machines, and careful unsafe usage for performance. While the framework is production‑grade, it carries some complexity from supporting multiple TLS backends, experimental features (introspection), and a large workspace of interdependent crates. Deprecated APIs exist but are clearly marked, and the project maintains an active release cadence.

Actix is a typed actor framework for Rust, built on top of Tokio. It provides a runtime for concurrent message-passing between actors, supporting both asynchronous and synchronous execution contexts. The framework defines core traits (Actor, Handler, Message) and provides an address-based communication model (Addr, Recipient) with bounded mailboxes and backpressure. It includes built-in supervision for fault tolerance, a system registry for service discovery, and a message broker for publish-subscribe patterns. The library is designed for building highly concurrent networked applications, and is the foundation for the actix-web HTTP framework. Architecturally, the system is centered around the System and Arbiter runtime components. Actors are spawned into contexts (Context for async, SyncContext for CPU-bound work) and communicate via typed messages. The address channel implementation uses a lock-free MPSC queue with capacity control. The framework provides a rich set of future and stream combinators (ActorFuture, ActorStream) that allow chaining asynchronous operations with access to actor state. External dependencies include tokio, futures, actix-rt, and crossbeam-channel. Key entry points include Actor::start(), Context::run(), System::new(), and the #[actix::main] macro. The library is extensively tested with unit tests, integration tests, and benchmarks. It is actively maintained with a clear changelog and migration guide.