express-validator

express-validator is an open-source middleware for Express.js that integrates validator.js to provide seamless server-side input validation and sanitization for incoming requests. It is designed for Node.js developers building Express applications who need a declarative, chainable API to validate form data, query parameters, and JSON bodies with minimal boilerplate. Its interesting because it combines the power of validator.js’s extensive validation library with Express’s middleware pattern, enabling clean, reusable validation logic that improves security and data integrity in web applications.