Class Validator Documentation

Decorator-based validation for TypeScript & JavaScript

class-validator uses validator.js under the hood to validate class instances with simple, composable decorators — in the browser or on Node.js.

Read the docs Visit sonicar.tech

Decorator and non-decorator based validation

Cross-platform: works in the browser and Node.js

Validates objects, arrays, and nested class instances

Custom validation classes and decorators

Dependency-injected validators via a service container

Rich set of 80+ built-in validators

Quick example

import { validate } from 'class-validator';
import { Length, Contains, IsInt, Min, Max, IsEmail } from 'class-validator';

export class Post {
  @Length(10, 20)
  title: string;

  @Contains('hello')
  text: string;

  @IsInt()
  @Min(0)
  @Max(10)
  rating: number;

  @IsEmail()
  email: string;
}

validate(new Post()).then(errors => {
  if (errors.length > 0) console.log('validation failed', errors);
});

This is an independent documentation example built by Sonicar Tech LLC and is not officially affiliated with the class-validator maintainers or TypeStack.