Automatically validate API requests and responses with OpenAPI 3.

Usage no npm install needed!

<script type="module">
  import openapiDataValidator from '';


OpenAPI Data Validator

Lightweight OpenAPI complete request model validator. Fast, unopinionated, full featured validator for API requests that utilize OpenAPI docs for API documentation.

npm version


It is simple, and that's all there is to it!

npm install openapi-data-validator --save
const { OpenApiValidator } = require('openapi-data-validator');
const spec = require('./openapi.json');

const openApiValidator = new OpenApiValidator({ apiSpec: spec });
const validator = openApiValidator.createValidator();

const newRequest = {
  method: 'GET',
  headers: { Authorization: 'Bearer Token' },
  query: { limit: 10 },
  body: { field: true },
  path: { user: 'userId' },

  // Matched openapi specification generic route
  route: request.route
await validator(newRequest);

Compile validator

For improved processing speed the validator can be pre-compiled from the spec

const openApiValidator = new OpenApiValidator({ apiSpec: spec, compiledFilePath: './compiledValidator.json' });
await openApiValidator.compileValidator();
// Later
const validator = await openApiValidator.loadValidation();

// ...
await validator(request);

Checkout the full: Async example


Why not just use AJV

AJV is the best, but there are some things that just are very OpenAPI specific that don't make sense to be in the validator. Don't need them? Great, go use AJV.

  • Top level defined Path parameters - AJV doesn't understand
  • Inline request body definitions, AJV doesn't understand schema defined in the method, it has to be in a component
  • Body Content-Type validation - Request bodies with multiple content types allowed