curl --request GET \
  --url https://api.lemlist.com/api/fields \
  --header 'Authorization: Basic <encoded-value>'

import requests

url = "https://api.lemlist.com/api/fields"

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/fields', 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/fields")

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/fields",
  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;
}

{
  "success": true,
  "data": {
    "contact": [
      {
        "name": "email",
        "label": "Email",
        "type": "text",
        "source": "default"
      },
      {
        "name": "firstName",
        "label": "First name",
        "type": "text",
        "source": "default"
      },
      {
        "name": "revenue",
        "label": "Annual Revenue",
        "type": "number",
        "source": "custom"
      },
      {
        "name": "leadStatus",
        "label": "leadStatus",
        "type": "text",
        "source": "crm_synced",
        "crmField": "hs_lead_status"
      }
    ],
    "company": [
      {
        "name": "linkedinUrl",
        "label": "LinkedIn URL",
        "type": "text",
        "source": "default"
      },
      {
        "name": "industry",
        "label": "Industry",
        "type": "text",
        "source": "custom"
      }
    ]
  }
}

{
  "success": false,
  "error": "Invalid entity parameter. Must be one of: contact, company"
}

{
  "error": "Unauthorized"
}

{
  "success": false,
  "error": "Method not allowed. Use GET."
}