---
title: "JSON Schema"
description: "Learn about files generated with @hey-api/openapi-ts."
url: "https://heyapi.dev/docs/openapi/typescript/plugins/schemas"
---

Schemas are located in the `schemas.gen.ts` file. This file contains runtime schemas generated from your OpenAPI specification definitions located in `#/components/schemas`. If you’re using OpenAPI 3.1, your schemas are fully JSON Schema compliant and can be used with other tools supporting JSON Schema.

## Configuration

[Section titled “Configuration”](#configuration)

You can modify the contents of `schemas.gen.ts` by configuring the `@hey-api/schemas` plugin. Note that you must specify the default plugins to preserve the default output.

* json

  openapi-ts.config.ts

  ```js
  export default {
    input: 'hey-api/backend', // sign up at app.heyapi.dev
    output: 'src/client',
    plugins: [
      // ...other plugins
      {
        name: '@hey-api/schemas',
        type: 'json',
      },
    ],
  };
  ```

* form

  openapi-ts.config.ts

  ```js
  export default {
    input: 'hey-api/backend', // sign up at app.heyapi.dev
    output: 'src/client',
    plugins: [
      // ...other plugins
      {
        name: '@hey-api/schemas',
        type: 'form',
      },
    ],
  };
  ```

* disabled

  openapi-ts.config.ts

  ```diff
  export default {
    input: 'hey-api/backend', // sign up at app.heyapi.dev
    output: 'src/client',
    plugins: [
      // ...other plugins
      -'@hey-api/schemas',
    ],
  };
  ```

## Output

[Section titled “Output”](#output)

Below is an example output generated in the `type: 'form'` style. Disabling schemas will not generate the `schemas.gen.ts` file.

schemas.gen.ts

```ts
export const PetSchema = {
  required: ['name'],
  properties: {
    id: {
      type: 'integer',
      format: 'int64',
      example: 10,
    },
    name: {
      type: 'string',
      example: 'doggie',
    },
  },
  type: 'object',
} as const;
```

## Usage

[Section titled “Usage”](#usage)

A great use case for schemas is client-side form input validation.

SomeComponent.ts

```ts
import { $Schema } from './client/schemas.gen';


const maxInputLength = $Schema.properties.text.maxLength;


if (userInput.length > maxInputLength) {
  throw new Error(`Text length can't exceed ${maxInputLength} characters!`);
}
```

## API

[Section titled “API”](#api)

You can view the complete list of options in the [UserConfig](https://github.com/hey-api/openapi-ts/blob/main/packages/openapi-ts/src/plugins/@hey-api/schemas/types.ts) interface.

## Examples

You can view live examples on [StackBlitz](https://stackblitz.com/orgs/github/hey-api/collections/openapi-ts-examples) or on [GitHub](https://github.com/hey-api/openapi-ts/tree/main/examples).