express-validator

express-validator is an active and widely used Express.js middleware library that provides a comprehensive suite of tools for validating and sanitizing request data. Currently at stable version 7.3.2, the library integrates directly with `validator.js`, offering a fluent API for defining validation chains for fields in the request body, query parameters, headers, or cookies. It typically releases patch and minor versions regularly, with major versions occurring less frequently (v7.0.0 was the first major update in almost four years). Key differentiators include its tight integration with Express's middleware system, robust error handling with `validationResult`, and extensive support for custom validators and sanitizers, making it a powerful solution for robust input validation in Node.js applications.