Vest - Declarative validations framework

Vest Documentation

Vest is a validation framework that looks and feels like a unit testing framework. It is designed to be easy to learn, highly maintainable, and framework-agnostic.

Write your validations as if they were unit tests, and run them in your app.

import { create, test, enforce } from 'vest';

const suite = create(data => {
  test('username', 'Username is required', () => {
    enforce(data.username).isNotBlank();
  });

  test('username', 'Username must be at least 3 chars', () => {
    enforce(data.username).longerThanOrEquals(3);
  });

  test('username', 'Username already taken', async () => {
    await doesUserExist(data.username);
  });
});

const result = await suite.run(formData);

Why Vest?

Writing form validations can be messy. Vest cleans it up by separating validation logic from feature logic and providing a familiar, powerful syntax.

💡 Easy to Learn

Vest adopts the syntax and style of unit testing frameworks (Mocha, Jest). If you've written a test, you already know Vest.

🎨 Framework Agnostic

React, Vue, Svelte, Angular, or Vanilla JS - Vest works everywhere. It doesn't depend on your UI library.

🛡️ Type Safe

Vest is written in TypeScript and provides first-class type support, including typed suites and results.

🔌 Standard Schema Support

Vest implements the Standard Schema spec, making it a drop-in replacement for Zod or Yup in libraries like React Hook Form.

⚡ SSR & Hydration

Built-in support for server-side validation and state hydration (runStatic, SuiteSerializer), enabling seamless full-stack validation flows.

🧩 Extendable & Composable

Create custom rules, compose existing ones, or use the optional schema validation (n4s) to enforce data structure.

Examples

Basic suite with result helpers

import { create, test, enforce } from 'vest';

const signupSuite = create(data => {
  test('email', 'Email is required', () => {
    enforce(data.email).isNotBlank().isEmail();
  });

  test('password', 'Password must be at least 8 characters', () => {
    enforce(data.password).isString().longerThanOrEquals(8);
  });
});

const result = await signupSuite.run({ email: '', password: 'short' });
result.hasErrors('email'); // true
result.getErrors('password'); // ['Password must be at least 8 characters']

Mixing sync and async validations

import { create, test, enforce } from 'vest';

const profileSuite = create(data => {
  test('handle', 'Handle must be unique', async () => {
    const exists = await handleExists(data.handle);
    enforce(exists).isFalse();
  });

  test('handle', 'Handle must be 3-16 characters', () => {
    enforce(data.handle)
      .isString()
      .longerThanOrEquals(3)
      .shorterThanOrEquals(16);
  });
});

const result = await profileSuite.run({ handle: 'ada' });
if (result.hasErrors()) {
  console.log(result.getErrors());
}

Installation

npm i vest

Getting Started

Check out the Vest Documentation for guides, API references, and examples.

Playgrounds

• React
• Vue
• Svelte
• Vanilla

Contribute

We welcome contributions! See CONTRIBUTING.md for details.