api.R

library(tidyverse)

## Something ------------------------------------ 

run.R

pr <- plumber::plumb('api.R')
pr$run(port = 1234, swagger = function(pr, spec, ...) {
  spec <- yaml::read_yaml('swagger.yml')
  spec
  })

swagger.yml

openapi: 3.0.3
info:
  description: >-
    An API
  version: 0.1.1.9000
  title: "An API"
tags:
  - name: "tag1"
    description: "tag1"
paths:
  /users:
    get:
      summary: "get endpoint"
      tags:
        - "tag1"
        # - "tags2"
      description: "an endpoint"
      parameters:
      - name: "parameter"
        in: "query"
        description: "a parameters"
        required: false
        schema:
          type: "string"
      responses:
        "204":
          description: "No match not found."