This is an example of using Crawlera with R.


library(httr)
r <- GET("http://httpbin.org/get",use_proxy(url = "proxy.crawlera.com", port = 8010, username = "<API_KEY>", password = ""))
r

Output:

Response [http://httpbin.org/get]
Date: 2019-11-28 04:35
Status: 200
Content-Type: application/json
Size: 394 B
{
"args": {},
"headers": {
"Accept": "application/json, text/xml, application/xml, */*",
"Accept-Encoding": "deflate, gzip",
"Host": "httpbin.org",
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36"
},
"origin": "64.137.115.132, 64.137.115.132",
"url": "https://httpbin.org/get"
...


Crawlera Certificate Authority can be downloaded here: crawlera-ca.crt.