Vapor is a server-side web framework for Swift, enabling type-safe, high-performance backend development. You write RESTful APIs in Swift, leveraging the language's strong type system, async/await concurrency, and modern syntax. Vapor includes routing, middleware, authentication, and database integration out-of-the-box. You build APIs using Swift, connect to databases (PostgreSQL, SQLite) via Fluent ORM, and deploy to Docker/cloud. Vapor codebases are expressive, type-safe, and maintainable—many errors caught at compile time, not runtime.