Years of old email in Gmail? Clear it in three steps.

import json, os, urllib.request

req = urllib.request.Request(
    "https://email59.com/v1/send",
    data=json.dumps({"from": "yourapp", "to": "user@gmail.com",
                     "subject": "Welcome", "text": "Thanks for signing up."}).encode(),
    headers={"Authorization": "Bearer " + os.environ["EMAIL59_KEY"],
             "Content-Type": "application/json"},
)
print(urllib.request.urlopen(req).read().decode())

const res = await fetch("https://email59.com/v1/send", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.EMAIL59_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    from: "yourapp",
    to: "user@gmail.com",
    subject: "Welcome",
    text: "Thanks for signing up.",
  }),
});
console.log(await res.json());

<?php
$ch = curl_init("https://email59.com/v1/send");
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        "Authorization: Bearer " . getenv("EMAIL59_KEY"),
        "Content-Type: application/json",
    ],
    CURLOPT_POSTFIELDS => json_encode([
        "from" => "yourapp",
        "to" => "user@gmail.com",
        "subject" => "Welcome",
        "text" => "Thanks for signing up.",
    ]),
]);
echo curl_exec($ch);
curl_close($ch);

using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;

var http = new HttpClient();
http.DefaultRequestHeaders.Authorization =
    new AuthenticationHeaderValue("Bearer", Environment.GetEnvironmentVariable("EMAIL59_KEY"));

var body = new StringContent(
    """{"from":"yourapp","to":"user@gmail.com","subject":"Welcome","text":"Thanks for signing up."}""",
    Encoding.UTF8, "application/json");

var res = await http.PostAsync("https://email59.com/v1/send", body);
Console.WriteLine(await res.Content.ReadAsStringAsync());

package main

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

func main() {
	body := []byte(`{"from":"yourapp","to":"user@gmail.com","subject":"Welcome","text":"Thanks for signing up."}`)
	req, _ := http.NewRequest("POST", "https://email59.com/v1/send", bytes.NewReader(body))
	req.Header.Set("Authorization", "Bearer "+os.Getenv("EMAIL59_KEY"))
	req.Header.Set("Content-Type", "application/json")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}