title: SwaggerUI/YAML - should NOT have additional properties additionalProperty: requestBody
body: <p>Designing an API using <strong>editor.swagger.io</strong> I find myself unable to add a requestBody attribute, getting an error I cannot address: </p>
  
  <pre><code>Schema error at paths['/projects/{projectId}/user'].post
  should NOT have additional properties
  additionalProperty: requestBody
  Jump to line 91
  </code></pre>
  
  <p>I don't understand what I'm doing wrong, especially after looking at the <a href="https://swagger.io/docs/specification/describing-request-body/" rel="noreferrer">requestBody documentation</a>. Research has brought me nothing other than the tendency for errors to be misleading.</p>
  
  <p>EDIT: From what the answers here have shown, it looks like the editor is supposed to use OpenAPI 2.0, but actually expects 3.0 while returning errors for both. I'd use some help on what to use, given that I've included a </p>
  
  <pre><code>swagger: "2.0"
  </code></pre>
  
  <p>line at the beginning of the document.
  While testing with <code>openapi: 3.0.0</code> as shown by @Mike in his answer, I just get more errors about allowed additional properties.</p>
  
  <p>Here's what's generating the error, line 91 being <code>post:</code> .</p>
  
  <pre><code>/projects/{projectId}/user:
        post:
          tags:
          - projects
          summary: Modify project user.
          operationId: modifyProjectUser
          parameters:
          - name: projectId
            in: path
            description: ID of the project
            required: true
            type: integer
            format: int32
          requestBody:
            content: 
              application/json:
                schema:
                $ref: '#/definitions/User'
          responses:
            "200":
              description: Successful operation
              schema:
                type: array
                items:
                  $ref: "#/definitions/User"
          security:
          - api_key: []
  </code></pre>