OpenAPI V3.0 Syntax CheatSheet

OpenApi 3.0 specification in Yaml format

contents can be written in separate files, and referenced with $ref: "./schemas/User.yaml" syntax

Example:

# Version of the openapi specificaiton
openapi: 3.0.0

# General metadata about this app
info:
  version: 1.0.0
  title: Simple App
  description: a simple app for demonstration purposes only
  termsOfService: /terms-of-use

# Relative URL to external documentation
externalDocs:
  url: /docs
  description: Find more info here

# list of backed urls:
servers:
  - url: https://example.io/v1
    description: example server 1
  - url: http://192.168.1.1/api/v2
    description: ip server 2
  - url: ws://192.168.1.1/api/v2
    description: websocket
  - url: wss://192.168.1.1/api/v2
    description: websocket secured
  - url: //192.168.1.1/api/v2

  # Complex server
  - url: https://{customerId}.saas-app.com:{port}/v2
    variables:
      customerId:
        default: demo
        description: Customer ID assigned by the service provider
      port:
        enum:
          - '443'
          - '8443'
        default: '443'

# Authentication:
components:
  securityScheme:

    # Basic Authentication
    BasicAuth:
      type: http
      scheme: basic

    # Bearer Authentication
    BearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT

    # Oauth2 Authentication
    oauth2:
      type: oauth2
      flows:
        authorizationCode:
          authorizationUrl: /oauth/dialog
          tokenUrl: /oauth/token

  # Templates for "Objects"
  schemas:
    User:
      type: object
      properties:
        id:
          type: integer
          format: int64
        name:
          type: string
      # properties not in required are implicit optional
      required:
        - id
        - name

security:
  - BasicAuth: []

# The endpoints
paths:
  # Basic Template
  /artists-v1/{id}:
    get: ...    # get an object
    post: ...   # create an object
    put: ...    # update the whole object
    patch: ...  # update some parts of the object
    delete: ... # delete the object
    
  # Simple get method
  /artists-v2:
    get:
      # An optional unique string to identify an operation
      operationId: lockerNoteSavePath
      # Tags to organize paths into components
      tags:
        - artists
      # A quick summary
      summary: Save user's locker note
      # A detailed description, also supports markdown
      description: >
        A detailed description of the operation.
        Use markdown for rich text representation,
        such as **bold**, *italic*, and [links](https://swagger.io).
      security:
        - bearerAuth: []
      parameters:
        ...
      responses:
        ...

  # Deprecated Operations:
  /pet/findByTags:
    get:
      deprecated: true

  # Override Global Servers
  /files:
    description: File upload and download operations
    servers:
      - url: https://files.example.com
        description: Override base path for all operations with the /files path

  # Parameters (Path, Query, Header, Cookie):
  /artists/{noteId}:
    get:
      security:
        - bearerAuth: []
      parameters:
        # Path Paramter
        - name: noteId
          in: path
          required: true
          schema:
            type: integer
            format: int64
        # Query Parameter
        - name: searchString
          in: query # => https://...../artists?searchString=lll
          required: true
          schema:
            type: integer
            format: int64
        # Header Parameter
        - in: header
          name: X-Request-ID
          schema:
            type: string
            format: uuid
          required: true
        # Cookie Parameter
        - in: cookie
          name: csrftoken
          schema:
            type: string


      responses:
        '200':
          description: Successfully returned a list of artists
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
                  required:
                    - username
                  properties:
                    artist_name:
                      type: string
                    artist_genre:
                      type: string
                    albums_recorded:
                      type: integer
                    username:
                      type: string

        '400':
          description: Invalid request
          content:
            application/json:
              schema:
                type: object
                properties:   
                  message:
                    type: string

  # Media type example
  # supported media types:
  #   - application/json
  #   - application/xml
  #   - application/x-www-form-urlencoded
  #   - multipart/form-data
  #   - text/plain; charset=utf-8
  #   - text/html
  #   - application/pdf
  #   - image/png
  /employees:
    get:
      summary: Returns a list of employees.
      responses:
        "200": # Response
          description: OK
          content: # Response body, multiple media types
            application/json: # One of media types
              schema:
                type: object
                properties:
                  id:
                    type: integer
                  name:
                    type: string
                  fullTime:
                    type: boolean
            application/xml: # Another media types
              schema:
                type: object
                properties:
                  id:
                    type: integer
                  name:
                    type: string
                  fullTime:
                    type: boolean