curl --request GET \
  --url https://api.lemlist.com/api/sequences/{sequenceId}/steps/{stepId}/ab-test \
  --header 'Authorization: Basic <encoded-value>'

import requests

url = "https://api.lemlist.com/api/sequences/{sequenceId}/steps/{stepId}/ab-test"

headers = {"Authorization": "Basic <encoded-value>"}

response = requests.get(url, headers=headers)

print(response.text)

const options = {method: 'GET', headers: {Authorization: 'Basic <encoded-value>'}};

fetch('https://api.lemlist.com/api/sequences/{sequenceId}/steps/{stepId}/ab-test', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

require 'uri'
require 'net/http'

url = URI("https://api.lemlist.com/api/sequences/{sequenceId}/steps/{stepId}/ab-test")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Basic <encoded-value>'

response = http.request(request)
puts response.read_body

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.lemlist.com/api/sequences/{sequenceId}/steps/{stepId}/ab-test",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "Authorization: Basic <encoded-value>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

{
  "stepId": "stp_V0JHmSpWiO0rxHUkz",
  "abTest": true,
  "emailTemplateBId": "etp_9aZ2k1QwErTyUiOp3",
  "subject": "Quick question, {{firstName}}",
  "message": "<div>Hi {{firstName}}, ...</div>"
}

The authentication you supplied is incorrect

route is available starting emailPro plan

{
  "error": "No A/B test variant on this step",
  "code": "SEQUENCE_AB_NO_VARIANT"
}

{
  "error": "Bad method"
}