# Ajv JSON schema validator

# Security and reliability for JavaScript applications

# Write less code

Ensure your data is valid once it is received

# Super fast & secure

Compiles your schemas to optimized JavaScript code

# Multi-standard

Use JSON Type Definition or JSON Schema

Ajv is used by a large number of JavaScript applications and libraries in all JavaScript environments - Node.js, browser, Electron apps, WeChat mini-apps etc.

It allows implementing complex data validation logic via declarative schemas for your JSON data, without writing code.

Out of the box, Ajv supports JSON Schema (drafts 04, 06, 07, 2019-09 and 2020-12) and JSON Type Definition (RFC8927 (opens new window)).

Learn Ajv

# What users say

Ajv stands out as the implementation of choice - it provides a rich API which many thousands of people use in production... Ajv is partly responsible for the success of JSON Schema.

Ben Hutton (opens new window), JSON Schema Specification Lead

ESLint (opens new window) has used Ajv for validating our complex configurations. Ajv has proven to be reliable over the years we’ve been using it and ESLint is proud to sponsor Ajv’s continued development.

Nicholas C. Zakas (opens new window), ESLint creator and TSC member

All quotes

# News

Ajv online event - May 20, 10am PT / 6pm UK

We will talk about:

  • new features of Ajv version 8.
  • the improvements sponsored by Mozilla's MOSS grant.
  • how Ajv is used in JavaScript applications.


  • Evgeny Poberezkin, the creator of Ajv.
  • Mehan Jayasuriya, Program Officer at Mozilla Foundation, leading the MOSS and other programs investing in the open source and community ecosystems.
  • Matteo Collina, Technical Director at NearForm and Node.js Technical Steering Committee member, creator of Fastify web framework.
  • Kin Lane, Chief Evangelist at Postman. Studying the tech, business & politics of APIs since 2010. Presidential Innovation Fellow during the Obama administration.
  • Ulysse Carion, the creator of JSON Type Definition specification.

Gajus Kuizinas will host the event.

Please register here.

Ajv version 8 is released!

Ajv version 8 has these new features:

Read more

Ajv supports JSON Type Definition

JSON Type Definition (JTD) is a new specification for defining JSON structures that is very simple to use, comparing with JSON Schema, less error prone, and it is published as RFC8927.

See Choosing schema language for a detailed comparison between JSON Schema and JSON Type definition and informal specification.

Read more
All news