How to define constant string in Swagger open api 3.0 [duplicate]

Answer 1

You can define a constant parameter as a required parameter with only one possible value

But if you have more than one parameter it can't be an constant. In the api all value can be changed if have an multiple choice.

Ref: https://swagger.io/docs/specification/2-0/describing-parameters/

Answer 2

As @Helen already pointed out, and as you can read in the linked answer, currently it does not seem to get any better than an enum with only one value. Full example that can be pasted into http://editor.swagger.io/:

{
  "openapi": "3.0.0",
  "info": {
    "title": "Some API",
    "version": "Some version"
  },
  "paths": {},
  "components": {
    "schemas": {
      "StatusCode": {
        "title": "StatusCode",
        "enum": [
          "The only possible value"
        ],
        "type": "string"
      }
    }
  }
}

There is a related topic on Github which is unsolved as of now: https://github.com/OAI/OpenAPI-Specification/issues/1313