Convert OpenAPI spec to JSON Schema
Published: 2021-02-09 14:05:13

---
title: Convert OpenAPI spec to JSON Schema
published: true
description: OpenAPI, jsonschema
tags: 
//cover_image: https://direct_url_to_image.jpg
---

I've created a Groovy script to convert from "OpenAPI" specification (aka Swagger file) to "JSON Schema".

https://github.com/adzubla/schema-convert

```bash
groovy SchemaConvert.groovy openapi-spec.yaml
```
 You can add the `-m` option to generate a schema compatible with MongoDB.
```bash
groovy SchemaConvert.groovy openapi-spec.yaml -m
```

# Sample execution

```bash
groovy SchemaConvert.groovy petstore.yaml
```

Input file `petstore.yaml`:

```yaml
openapi: "3.0.0"
info:
  version: 1.0.0
  title: Swagger Petstore
  license:
    name: MIT
servers:
  - url: http://petstore.swagger.io/v1
paths:
  /pets:
    get:
      summary: List all pets
      operationId: listPets
      tags:
        - pets
      parameters:
        - name: limit
          in: query
          description: How many items to return at one time (max 100)
          required: false
          schema:
            type: integer
            format: int32
      responses:
        '200':
          description: A paged array of pets
          headers:
            x-next:
              description: A link to the next page of responses
              schema:
                type: string
          content:
            application/json:    
              schema:
                $ref: "#/components/schemas/Pets"
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
    post:
      summary: Create a pet
      operationId: createPets
      tags:
        - pets
      responses:
        '201':
          description: Null response
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
  /pets/{petId}:
    get:
      summary: Info for a specific pet
      operationId: showPetById
      tags:
        - pets
      parameters:
        - name: petId
          in: path
          required: true
          description: The id of the pet to retrieve
          schema:
            type: string
      responses:
        '200':
          description: Expected response to a valid request
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Pets"
        default:
          description: unexpected error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
components:
  schemas:
    Pets:
      type: array
      items:
        $ref: "#/components/schemas/Pet"
    Pet:
      required:
        - id
        - name
      properties:
        id:
          type: integer
          format: int64
        name:
          type: string
        tag:
          type: string
    Error:
      required:
        - code
        - message
      properties:
        code:
          type: integer
          format: int32
        message:
          type: string
```

Output file `petstore.json`:
```json
{"key": "value"}
```