Untitled

// swagger.yml

---
swagger: '2.0'
info:
  version: 3.0.1
  title: The coolest API
paths:
  /:
    get:
      produces:
        - text/html
      responses:
        200:
          description: Return index page
          schema:
            type: string

// go file

swaggerSpec, err := loads.Analyzed(restapi.SwaggerJSON, "")
...
api := operations.NewYOURAPI(swaggerSpec)
api.HTMLProducer = runtime.TextProducer()
...

api.GetHandler = operations.GetHandlerFunc(
		func(params operations.GetParams) middleware.Responder {
			return operations.NewGetOK().WithPayload("<!DOCTYPE html><html> <body> <h1>My First Heading</h1> <p>My first paragraph.</p> </body> </html>")
		})

...