Express Validation

express-validation v4.1.1 is an Express middleware that validates request parameters (body, query, headers, params, cookies, signedCookies) using Joi schemas. It returns structured error responses when validation fails and integrates with Express error handlers. The library has a hard dependency on Joi v17.x.x and ships with TypeScript definitions. It is actively maintained with regular releases, and provides multiple error format options including keyByField. Compared to alternatives like express-validator, it uses Joi directly rather than its own validator.