Vest is a declarative validation framework that allows developers to write form validations using a syntax similar to unit testing frameworks like Jest or Mocha. It is designed to be framework-agnostic, type-safe, and easy to learn, making it suitable for validating forms in React, Vue, Svelte, Angular, or vanilla JavaScript applications. Vest also supports server-side validation, schema integration, and composable rules for maintainable and scalable validation logic.