curl --request DELETE \
  --url https://api.hubapi.com/crm/v3/objects/postal_mail/{postalMailId}

import requests

url = "https://api.hubapi.com/crm/v3/objects/postal_mail/{postalMailId}"

response = requests.delete(url)

print(response.text)

const options = {method: 'DELETE'};

fetch('https://api.hubapi.com/crm/v3/objects/postal_mail/{postalMailId}', 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.hubapi.com/crm/v3/objects/postal_mail/{postalMailId}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "DELETE",
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://api.hubapi.com/crm/v3/objects/postal_mail/{postalMailId}"

	req, _ := http.NewRequest("DELETE", url, nil)

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.delete("https://api.hubapi.com/crm/v3/objects/postal_mail/{postalMailId}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.hubapi.com/crm/v3/objects/postal_mail/{postalMailId}")

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

request = Net::HTTP::Delete.new(url)

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

This response has no body data.

{
  "message": "Invalid input (details will vary based on the error)",
  "correlationId": "aeb5f871-7f07-4993-9211-075dc63e7cbf",
  "category": "VALIDATION_ERROR",
  "links": {
    "knowledge-base": "https://www.hubspot.com/products/service/knowledge-base"
  }
}