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

import requests

url = "https://api.lemlist.com/api/contacts/{idOrEmail}"

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/contacts/{idOrEmail}', 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/contacts/{idOrEmail}")

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/contacts/{idOrEmail}",
  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;
}

{
  "_id": "ctc_xW8Ou6C03Csv8vatp",
  "teamId": "tea_8QvkOiBfPdb2ZRhHi",
  "fullName": "John Doe",
  "email": "support@lemlist.com",
  "fields": {
    "firstName": "John",
    "jobTitle": "Growth Engineer",
    "lastName": "Doe",
    "industry": "Technology",
    "isActiveInCampaigns": false,
    "lastCampaign": "NEW TO DELETE",
    "lastLeadMarkedAsInterestedDate": "2025-10-28T02:12:31.971Z",
    "leadStatus": "Marked as not Interested by api"
  },
  "campaigns": [
    {
      "campaignId": "cam_bSn8EORHQxbWPjHvu",
      "campaignState": "running",
      "leadState": "review",
      "leadId": "lea_fiDpiGV585wy3Oii2"
    }
  ],
  "ownerId": "usr_ahfFktBBHUIxbVG5P",
  "createdAt": "2025-10-28T00:40:37.917Z",
  "createdBy": "usr_ahfFktBBHUIxbVG5P",
  "unsubscribed": false
}

{
  "error": "Match error: Failed Match.Where validation in field [0]"
}

The authentication you supplied is incorrect

{
  "error": "Contact not found"
}