Node.js is used to build small APIs using five popular frameworks: Express.js, Koa.js, Restify, and Hapi. Each framework has its own strengths and weaknesses, such as Express.js being lightweight and unopinionated, while Koa.js is async-friendly and lacks built-in features, and hapi being extremely scalable and enterprise-ready. The choice of framework ultimately depends on the developer's familiarity with the best practices for optimizing code performance and the need for specific features like routing and response types.