Common Rust Crates for Web Development

Last updated: April 13, 2025

Table of Contents

1. Introduction: The Rust Ecosystem

While Rust's standard library provides core functionality, real-world applications rely heavily on external libraries, known as crates in the Rust ecosystem. These crates are typically shared and discovered via the official registry, crates.io.

For web development, a number of crates have become de facto standards or popular choices for handling common tasks like asynchronous operations, routing HTTP requests, interacting with databases, and handling data formats like JSON. This guide provides an overview of some essential and commonly used crates for building web applications and APIs in Rust.

Make sure you're familiar with adding dependencies using Cargo, as covered in our Getting Started with Rust guide.

2. Async Runtime: Tokio

  • Crate: tokio
  • Purpose: Provides the asynchronous runtime necessary for building non-blocking, concurrent applications in Rust. Most popular Rust web frameworks are built on top of Tokio.
  • Key Features: Event loop, asynchronous tasks (futures), timers, synchronization primitives (mutexes, channels), async file system and network I/O.
  • Usage: Typically enabled via the #[tokio::main] macro on your main function. Essential for using async/await with libraries designed for it.

3. Web Frameworks

These crates provide the structure for handling HTTP requests, routing, middleware, and responses.

3.1 Actix Web

  • Crate: actix-web
  • Purpose: A powerful, pragmatic, and extremely performant web framework. See our guide: Building a Simple Web API with Rust and Actix Web.
  • Key Features: Async request handling, robust routing, middleware support, WebSocket support, type-safe request/response handling, built on the Actix actor framework (though direct actor use is optional).

3.2 Axum

  • Crate: axum
  • Purpose: A web application framework focusing on ergonomics and modularity, built by the Tokio team.
  • Key Features: Tightly integrated with the Tokio ecosystem (Tower for middleware, Hyper for HTTP), composable routing, ergonomic handlers using function arguments for extraction, minimal boilerplate. Gaining popularity rapidly.

3.3 Rocket

  • Crate: rocket
  • Purpose: A framework focused on ease of use, type safety, and expressiveness, often compared to frameworks like Ruby on Rails or Python's Flask/Django in terms of developer experience.
  • Key Features: Extensive use of macros for routing and request handling, built-in templating and form handling support, managed state. Historically relied on nightly Rust features, but recent versions have improved stable Rust compatibility.

4. Serialization/Deserialization: Serde

  • Crate: serde (and related crates like serde_json, serde_yaml)
  • Purpose: The standard framework for serializing and deserializing Rust data structures efficiently. Essential for handling JSON, TOML, YAML, and other data formats common in web APIs.
  • Key Features: Uses procedural macros (#[derive(Serialize, Deserialize)]) to automatically implement serialization logic for structs and enums, highly performant, supports a wide range of data formats through companion crates.
  • Usage: Almost universally used when dealing with JSON request/response bodies in web frameworks.

5. Database Access

Interacting with databases (both SQL and NoSQL) requires specific crates.

5.1 SQLx

  • Crate: sqlx
  • Purpose: A modern, async SQL toolkit for Rust.
  • Key Features: Fully asynchronous (integrates well with Tokio/async-std), compile-time query checking against a live database (optional but powerful feature), support for PostgreSQL, MySQL, SQLite, MSSQL, connection pooling, mapping rows to Rust structs.

5.2 Diesel

  • Crate: diesel
  • Purpose: A popular Object-Relational Mapper (ORM) and query builder for Rust.
  • Key Features: Provides a type-safe Domain Specific Language (DSL) for building SQL queries in Rust code, handles migrations, supports PostgreSQL, MySQL, SQLite. Primarily synchronous, though async support is developing. Often seen as having a steeper learning curve than SQLx but offers more abstraction.

6. Error Handling

While Rust's standard library provides Result, these crates simplify handling errors across different libraries. See our Error Handling in Rust guide.

6.1 Anyhow

  • Crate: anyhow
  • Purpose: Provides a flexible anyhow::Error type used for easy error handling in applications (less common in libraries). Makes it simple to return and propagate errors without needing to define complex custom error types immediately.
  • Key Features: Simple creation of errors with context, easy wrapping of different error types, integrates well with the ? operator.

6.2 Thiserror

  • Crate: thiserror
  • Purpose: A derive macro helper for creating custom error types, particularly useful for libraries.
  • Key Features: Reduces boilerplate when defining custom error enums that implement the standard std::error::Error trait, integrates well with the ? operator's From trait requirement.

7. Logging

  • Crate: log / tracing + Facades (env_logger, tracing_subscriber)
  • Purpose: Provides logging and structured event tracing capabilities.
  • Key Features: log is a simpler facade; tracing offers more advanced structured logging and spans. Need to be paired with a subscriber/logger implementation (like env_logger, tracing_subscriber, etc.) to actually output logs. Essential for monitoring and debugging web applications.

8. Configuration Management

  • Crate: config
  • Purpose: Handles application configuration from various sources (files, environment variables, etc.).
  • Key Features: Merges configuration from multiple sources, supports different file formats (YAML, TOML, JSON), environment variable overrides, type-safe access to configuration values.

9. Conclusion

The Rust ecosystem for web development is vibrant and rapidly maturing. While it might not have the sheer volume of libraries as Node.js or Python yet, powerful and high-quality crates exist for nearly every common web development task.

Key crates like Tokio provide the async foundation, frameworks like Actix Web, Axum, or Rocket handle HTTP, Serde manages data serialization, SQLx or Diesel connect to databases, and others handle errors, logging, and configuration. By leveraging these well-maintained crates, developers can build performant, safe, and scalable web applications in Rust.

10. Additional Resources

Related Articles

External Resources

  • crates.io - The official Rust Crate Registry
  • Are we web yet? - Tracks the status of Rust's web development ecosystem
  • Awesome Rust - A curated list of Rust resources and libraries