ajv vs zod vs joi vs yup vs typanion | Data Validation Libraries

Package	Downloads	Stars	Size	Issues	Publish	License

ajv	176,210,711	14,498	1.03 MB	305	a year ago	MIT
zod	63,120,658	40,933	4.03 MB	271	13 days ago	MIT
joi	14,732,064	21,187	557 kB	186	17 days ago	BSD-3-Clause
yup	8,875,706	23,653	270 kB	238	3 months ago	MIT
typanion	2,992,771	275	133 kB	19	2 years ago	MIT

TypeScript Support

ajv:
ajv provides TypeScript definitions, but its primary focus is on JSON Schema validation rather than TypeScript type inference. It is more suited for projects where JSON Schema compliance is critical.
zod:
zod is a TypeScript-first library that provides the best type inference among these options. It is designed to work seamlessly with TypeScript, making it ideal for projects that prioritize type safety and inference.
joi:
joi has good TypeScript support, but it was originally designed for JavaScript. Recent versions have improved type definitions, making it more type-safe and easier to use in TypeScript projects.
yup:
yup offers excellent TypeScript support, with well-defined types and interfaces that make it easy to use in TypeScript projects. It provides good type inference for schemas and validation functions.
typanion:
typanion is designed with TypeScript in mind, offering first-class support for TypeScript types and type safety. It leverages TypeScript's type system to provide more accurate type inference and validation.

Asynchronous Validation

ajv:
ajv supports asynchronous validation out of the box, especially for validating data against schemas that include asynchronous constraints or custom keywords.
zod:
zod supports asynchronous validation, particularly for validating data with async functions or promises. It allows for flexible integration of async validation logic.
joi:
joi supports asynchronous validation, allowing validators to return promises. This is useful for scenarios like validating data against external sources or performing async checks.
yup:
yup has built-in support for asynchronous validation, allowing you to define async validation rules and handle promises in your validation logic.
typanion:
typanion supports asynchronous validation, making it suitable for scenarios where validation requires async operations, such as checking values against a database or an API.

Error Handling

ajv:
ajv provides detailed error messages and supports custom error formatting. It allows you to access validation errors in a structured way, making it easier to handle and display them.
zod:
zod offers structured error handling with detailed error messages. It provides a clear API for accessing validation errors, making it easy to integrate with UI frameworks and handle errors effectively.
joi:
joi offers comprehensive error handling with detailed messages. It provides a rich error object that includes information about the validation failure, making it easy to customize error handling and messaging.
yup:
yup provides clear and customizable error messages. It allows you to access validation errors in a structured format, making it easy to display errors in user interfaces or handle them programmatically.
typanion:
typanion provides structured error handling that integrates with TypeScript's type system. It allows for clear and consistent error reporting, making it easier to handle validation errors in a type-safe manner.

Schema Definition

ajv:
ajv uses JSON Schema for schema definition, which is a standardized format for describing the structure of JSON data. This makes it highly interoperable and suitable for projects that require strict schema compliance.
zod:
zod uses a declarative, TypeScript-first approach for schema definition. It is designed to be simple and intuitive, with a focus on type safety and minimal boilerplate code.
joi:
joi uses a fluent API for schema definition, allowing for expressive and readable validation rules. It is highly customizable and supports complex nested validations, making it versatile for various use cases.
yup:
yup uses a fluent API similar to joi for defining schemas. It is designed to be simple and intuitive, making it easy to create both simple and complex validation rules.
typanion:
typanion uses a TypeScript-based approach for schema definition, leveraging TypeScript's type system to enforce validation rules. This makes it particularly suited for TypeScript projects where type safety is a priority.

Ease of Use: Code Examples

ajv:

JSON Schema Validation with ajv

const Ajv = require('ajv');
const ajv = new Ajv();
const validate = ajv.compile({
  type: 'object',
  properties: {
    name: { type: 'string' },
    age: { type: 'integer', minimum: 0 }
  },
  required: ['name', 'age'],
  additionalProperties: false
});
const valid = validate({ name: 'John', age: 30 });
if (!valid) console.log(validate.errors);

zod:

Zod Validation Example

import { z } from 'zod';
const schema = z.object({
  name: z.string(),
  age: z.number().min(0)
});
const result = schema.safeParse({ name: 'John', age: 30 });
if (!result.success) {
  console.error(result.error.format());
} else {
  console.log('Valid:', result.data);
}

joi:

Object Validation with joi

const Joi = require('joi');
const schema = Joi.object({
  name: Joi.string().required(),
  age: Joi.number().integer().min(0).required()
});
const { error, value } = schema.validate({ name: 'John', age: 30 });
if (error) console.log(error.details);

yup:

Yup Validation Example

const yup = require('yup');
const schema = yup.object().shape({
  name: yup.string().required(),
  age: yup.number().integer().min(0).required()
});
schema.validate({ name: 'John', age: 30 })
  .then((value) => console.log('Valid:', value))
  .catch((err) => console.log('Error:', err.errors));

typanion:

Type-Safe Validation with typanion

import { createValidator } from 'typanion';
const validate = createValidator({
  name: (value) => typeof value === 'string',
  age: (value) => typeof value === 'number' && value >= 0
});
const isValid = validate({ name: 'John', age: 30 });
if (!isValid) console.error('Validation failed');