curl --request PATCH \
  --url https://api-sandbox.revolv3.com/api/Customers/{customerId} \
  --header 'Content-Type: application/json-patch+json' \
  --header 'x-revolv3-token: <api-key>' \
  --data '
{
  "merchantCustomerRefId": "1234-5678-9101",
  "firstName": "Jonathan",
  "lastName": null
}
'

import requests

url = "https://api-sandbox.revolv3.com/api/Customers/{customerId}"

payload = {
    "merchantCustomerRefId": "1234-5678-9101",
    "firstName": "Jonathan",
    "lastName": None
}
headers = {
    "x-revolv3-token": "<api-key>",
    "Content-Type": "application/json-patch+json"
}

response = requests.patch(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'PATCH',
  headers: {'x-revolv3-token': '<api-key>', 'Content-Type': 'application/json-patch+json'},
  body: JSON.stringify({merchantCustomerRefId: '1234-5678-9101', firstName: 'Jonathan', lastName: null})
};

fetch('https://api-sandbox.revolv3.com/api/Customers/{customerId}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api-sandbox.revolv3.com/api/Customers/{customerId}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "PATCH",
  CURLOPT_POSTFIELDS => json_encode([
    'merchantCustomerRefId' => '1234-5678-9101',
    'firstName' => 'Jonathan',
    'lastName' => null
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json-patch+json",
    "x-revolv3-token: <api-key>"
  ],
]);

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

curl_close($curl);

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

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api-sandbox.revolv3.com/api/Customers/{customerId}"

	payload := strings.NewReader("{\n  \"merchantCustomerRefId\": \"1234-5678-9101\",\n  \"firstName\": \"Jonathan\",\n  \"lastName\": null\n}")

	req, _ := http.NewRequest("PATCH", url, payload)

	req.Header.Add("x-revolv3-token", "<api-key>")
	req.Header.Add("Content-Type", "application/json-patch+json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.patch("https://api-sandbox.revolv3.com/api/Customers/{customerId}")
  .header("x-revolv3-token", "<api-key>")
  .header("Content-Type", "application/json-patch+json")
  .body("{\n  \"merchantCustomerRefId\": \"1234-5678-9101\",\n  \"firstName\": \"Jonathan\",\n  \"lastName\": null\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api-sandbox.revolv3.com/api/Customers/{customerId}")

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

request = Net::HTTP::Patch.new(url)
request["x-revolv3-token"] = '<api-key>'
request["Content-Type"] = 'application/json-patch+json'
request.body = "{\n  \"merchantCustomerRefId\": \"1234-5678-9101\",\n  \"firstName\": \"Jonathan\",\n  \"lastName\": null\n}"

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

{
  "customerId": 1,
  "merchantCustomerRefId": "1234-5678-9101",
  "firstName": "Jonathan",
  "lastName": "Doe",
  "billingAddresses": [
    {
      "addressId": 1,
      "addressLine1": "100 Main Street",
      "addressLine2": null,
      "city": "Santa Ana",
      "state": "CA",
      "postalCode": "90000",
      "phoneNumber": null,
      "email": null,
      "country": "US"
    }
  ],
  "shippingAddresses": [
    {
      "addressId": 2,
      "addressLine1": "101 First Street",
      "addressLine2": null,
      "city": "Costa Mesa",
      "state": "CA",
      "postalCode": "90001",
      "phoneNumber": null,
      "email": null,
      "country": "US"
    }
  ],
  "taxAddresses": [],
  "subscriptions": []
}

{
  "message": "Unable to perform the request action with provided data."
}

{
  "message": "Attempted to perform an unauthorized operation."
}

{
  "message": "Unable to find an entity with the provided data."
}