ajv VS class-validator

Compare ajv vs class-validator and see what are their differences.

ajv

The fastest JSON schema Validator. Supports JSON Schema draft-04/06/07/2019-09/2020-12 and JSON Type Definition (RFC8927) (by ajv-validator)

class-validator

Decorator-based property validation for classes. (by typestack)
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ajv class-validator
59 28
13,279 10,386
1.2% 1.8%
6.0 9.3
4 days ago 7 days ago
TypeScript TypeScript
MIT License MIT License
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.

ajv

Posts with mentions or reviews of ajv. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2023-10-03.
  • 6 Reasons why JSON Schema is worth your time
    5 projects | dev.to | 3 Oct 2023
    In the JavaScript ecosystem you can use the excellent AJV package to validate any JavaScript object against a JSON schema. This is especially useful to ensure that API contracts are maintained when communicating with other services.
  • Migrate Your Express Application to Fastify
    12 projects | dev.to | 5 Jul 2023
    Since Fastify supports schema validation with Ajv, the validate module is no longer required on the /shorten route, and we can specify the JSON schema directly on the route. The controllers for both routes will largely remain the same, except that the res parameter is renamed to reply as before:
  • Has anybody used Typia library?
    3 projects | /r/typescript | 27 Jun 2023
    There's a ton of schema validators out there and most devs have their personal favorite. Mine was zod and is now typebox + ajv.
  • Advanced Fastify: Hooks, Middleware, and Decorators
    4 projects | dev.to | 31 May 2023
    Fastify uses JSON schema to define the validation rules for each route's input payload, which includes the request body, query string, parameters, and headers. The JSON schema is a standard format for defining the structure and constraints of JSON data, and Fastify uses Ajv, one of the fastest and most efficient JSON schema validators available.
  • Getting Started with Fastify for Node.js
    4 projects | dev.to | 5 May 2023
    In Fastify, JSON schema validation is a built-in feature that allows you to validate the payload of incoming requests before the handler function is executed. This ensures that incoming data is in the expected format and meets the required criteria for your business logic. Fastify's JSON schema validation is powered by the Ajv library, a fast and efficient JSON schema validator.
  • How can we map data from JSON to typescript object efficiently?
    4 projects | /r/reactjs | 30 Apr 2023
    I think you're looking for a json schema validator like Ajv or Zod.
  • 5 useful JSON tools to improve your productivity
    4 projects | dev.to | 11 Apr 2023
    We can use JSON Schema to validate that our data adheres to a specific structure. Ajv is one popular validator tool for JavaScript applications that allows us to create a schema and then validate JSON against that schema. Here's an example of using Ajv to validate one of the above JSON examples against a schema:
  • Ask HN: JSON API object type definitions and validation in 2023?
    2 projects | news.ycombinator.com | 23 Mar 2023
    Hey HN,

    We're designing a new system and have been kicking the can about JSON object definitions and validation. Soon we need to settle on a system to validate API request bodies and provide helpful error messages.

    In the past, I've used JSON Schema ( https://json-schema.org/ ) to define definitions and ajv ( https://ajv.js.org/ ) to validate, but it's a bit verbose and ajv validation errors are more cryptic than I'd like to deal with.

    TypeSchema looks interesting. It seems solid (and perhaps stable?), but development hasn't been active for 2 years. It also looks like we'd still need to generate JSON Schema and choose a validation library

    Anyway, I'm very curious how others are approaching this problem. How do you organize and generate validations for your type definitions? What libraries do you use to validate and provide human readable error messages?

    Thank you!

  • Node.js Express API Data Validation: Techniques and Examples
    2 projects | /r/node | 16 Mar 2023
    Fastify uses ajv for data validation under the hood. I'd recommend ArkType or Zod
  • How to handle forms in a good way?
    2 projects | /r/sveltejs | 19 Jan 2023
    I've used Felte to reduce form boilerplate. Felte supports several different validation libraries like Zod. I actually used a custom validation function with ajv (which uses JSON schema).

class-validator

Posts with mentions or reviews of class-validator. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2024-01-16.

What are some alternatives?

When comparing ajv and class-validator you can also consider the following projects:

zod - TypeScript-first schema validation with static type inference

joi - The most powerful data validation library for JS [Moved to: https://github.com/hapijs/joi]

Yup - Dead simple Object schema validation

class-transformer - Decorator-based transformation, serialization, and deserialization between objects and classes.

tv4 - Tiny Validator for JSON Schema v4

TypeORM - ORM for TypeScript and JavaScript. Supports MySQL, PostgreSQL, MariaDB, SQLite, MS SQL Server, Oracle, SAP Hana, WebSQL databases. Works in NodeJS, Browser, Ionic, Cordova and Electron platforms.

typebox - Json Schema Type Builder with Static Type Resolution for TypeScript

io-ts - Runtime type system for IO decoding/encoding

Superstruct - A simple and composable way to validate data in JavaScript (and TypeScript).