Leptos

Leptos is a full-stack, isomorphic web framework for Rust that lets you build interactive applications with a fine-grained reactive system inspired by SolidJS. You write your UI once with the declarative view! macro and run it on both the server and in the browser via WebAssembly, sharing the same components across server-side rendering, hydration, and client-side interactivity.

Beyond the reactive core, Leptos ships a batteries-included ecosystem — a router, meta/head management, server functions for typed client-server calls, and integrations for Axum and Actix — making it a complete foundation for shipping production Rust web apps.

What You Get

• A fine-grained reactive runtime (signals, memos, effects) that updates only the DOM nodes that actually change
• A declarative view! macro with a JSX-like syntax, plus an alternative builder API
• Server functions for type-safe client-server communication without hand-writing API endpoints
• First-class SSR, streaming, and hydration with integrations for Axum and Actix
• An official router and meta/head management crate for complete application structure

Common Use Cases

• Building interactive single-page applications entirely in Rust and WebAssembly
• Server-rendered, SEO-friendly web apps with client-side hydration
• Full-stack Rust apps that share types and logic between server and browser via server functions
• Performance-critical dashboards and UIs where fine-grained updates matter

Under The Hood

Architecture - Leptos is a Cargo workspace split into focused crates: reactive_graph implements the fine-grained signal/memo/effect runtime, tachys provides the rendering engine, leptos_macro compiles the view! macro, leptos_dom and leptos_server handle DOM output and server functions, and router/meta add navigation and head management. The top-level leptos crate re-exports these into a unified API, with integrations under integrations/ wiring SSR and hydration into Axum and Actix.

Tech Stack - Written entirely in Rust targeting both native and wasm32-unknown-unknown, using web-sys/wasm-bindgen for browser bindings, serde/serde_json for server-function serialization, and typed-builder, thiserror, and rustc-hash internally. The workspace pins its own member crates by path and version for coordinated releases.

Code Quality - The codebase is organized into small single-responsibility crates with a large examples/ directory (counters, hackernews, SSR variants, islands, routing) that doubles as integration coverage. Code follows idiomatic Rust with a shared rustfmt.toml, workspace-wide dependency management, and an ARCHITECTURE.md documenting internals.

API Design - The public API centers on a small set of ergonomic primitives — signal(), #[component], and the view! macro — that feel familiar to React/SolidJS developers while remaining type-safe. Server functions collapse client-server boundaries into ordinary annotated Rust functions, and extensive documentation, a book, and playground examples smooth the initial learning curve despite the inherent complexity of Rust/WASM tooling.