Rust modules organize application code into named areas, separating functionality such as HTTP handlers, database access, models, and application state. This structure supports clear responsibility boundaries as a web application grows. section 1.3.2 section 6.4
pub mod auth; #1 pub mod course; #2
A handler module can expose authentication and course functionality as separate public submodules. section 9.4
In the web application, module organization develops alongside its features:
- An initial application groups database access, errors, handlers, models, routes, and state under a module configured with `mod.rs`. section 8.1
- As course maintenance is added, handler files are split into authentication and course modules; routes import their handlers, and the application configures the routes. section 9.4
