SMTP Integration

Overview

Gorillaa Mail exposes a standard SMTP server alongside the REST API. If your framework, CMS, or language already has SMTP support built in (WordPress, Django, Rails, PHP mail(), etc.), you can start sending through Gorillaa without writing any API integration code. Both interfaces use the same authentication, domain verification, and delivery pipeline — you get the same tracking, analytics, and deliverability regardless of which method you use.

SMTP server details

Setting	Value
Host	`smtp.gorillaa.one`
Port (STARTTLS)	`587` — Recommended
Port (TLS)	`465` — Implicit TLS
Port (Alt)	`2525` — Use when ISP blocks 587
Username	`gorillaa`
Password	Your API key (e.g. `grl_live_xxxx...`)
Encryption	TLS 1.3 required on all ports
Max message size	25 MB

The username is always the literal string gorillaa. Your API key goes in the password field.

Your API key must have the email:send scope to send emails via SMTP. Keys without this scope will be rejected at authentication.

Quick start

import nodemailer from "nodemailer";

const transport = nodemailer.createTransport({
  host: "smtp.gorillaa.one",
  port: 587,
  secure: false, // STARTTLS — upgraded automatically
  auth: {
    user: "gorillaa",
    pass: process.env.GORILLAA_API_KEY,
  },
});

await transport.sendMail({
  from: "[email protected]",
  to: "[email protected]",
  subject: "Hello from Gorillaa!",
  html: "<h1>It works!</h1>",
});

import smtplib
from email.mime.text import MIMEText
import os

msg = MIMEText("<h1>It works!</h1>", "html")
msg["From"] = "[email protected]"
msg["To"] = "[email protected]"
msg["Subject"] = "Hello from Gorillaa!"

with smtplib.SMTP("smtp.gorillaa.one", 587) as server:
    server.starttls()
    server.login("gorillaa", os.environ["GORILLAA_API_KEY"])
    server.send_message(msg)

use PHPMailer\PHPMailer\PHPMailer;

$mail = new PHPMailer(true);
$mail->isSMTP();
$mail->Host       = 'smtp.gorillaa.one';
$mail->SMTPAuth   = true;
$mail->Username   = 'gorillaa';
$mail->Password   = getenv('GORILLAA_API_KEY');
$mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
$mail->Port       = 587;

$mail->setFrom('[email protected]', 'Your App');
$mail->addAddress('[email protected]');
$mail->Subject = 'Hello from Gorillaa!';
$mail->isHTML(true);
$mail->Body = '<h1>It works!</h1>';

$mail->send();

require "mail"

Mail.defaults do
  delivery_method :smtp, {
    address: "smtp.gorillaa.one",
    port: 587,
    user_name: "gorillaa",
    password: ENV["GORILLAA_API_KEY"],
    authentication: :plain,
    enable_starttls_auto: true,
  }
end

Mail.deliver do
  from    "[email protected]"
  to      "[email protected]"
  subject "Hello from Gorillaa!"
  html_part do
    content_type "text/html; charset=UTF-8"
    body "<h1>It works!</h1>"
  end
end

package main

import (
    "net/smtp"
    "os"
)

func main() {
    auth := smtp.PlainAuth("", "gorillaa", os.Getenv("GORILLAA_API_KEY"), "smtp.gorillaa.one")

    msg := []byte("From: [email protected]\r\n" +
        "To: [email protected]\r\n" +
        "Subject: Hello from Gorillaa!\r\n" +
        "Content-Type: text/html\r\n\r\n" +
        "<h1>It works!</h1>\r\n")

    smtp.SendMail("smtp.gorillaa.one:587", auth, "[email protected]",
        []string{"[email protected]"}, msg)
}

# settings.py
EMAIL_BACKEND = "django.core.mail.backends.smtp.EmailBackend"
EMAIL_HOST = "smtp.gorillaa.one"
EMAIL_PORT = 587
EMAIL_USE_TLS = True
EMAIL_HOST_USER = "gorillaa"
EMAIL_HOST_PASSWORD = os.environ["GORILLAA_API_KEY"]
DEFAULT_FROM_EMAIL = "[email protected]"

# views.py
from django.core.mail import send_mail

send_mail(
    subject="Hello from Gorillaa!",
    message="Plain text version",
    html_message="<h1>It works!</h1>",
    from_email="[email protected]",
    recipient_list=["[email protected]"],
)

// .env
MAIL_MAILER=smtp
MAIL_HOST=smtp.gorillaa.one
MAIL_PORT=587
MAIL_USERNAME=gorillaa
MAIL_PASSWORD=your_gorillaa_api_key
MAIL_ENCRYPTION=tls
MAIL_FROM_ADDRESS=you@yourdomain.com
MAIL_FROM_NAME="Your App"

Install a plugin like WP Mail SMTP or Post SMTP, then configure:

Field	Value
SMTP Host	`smtp.gorillaa.one`
SMTP Port	`587`
Encryption	TLS
Username	`gorillaa`
Password	Your API key
From Email	`[email protected]`

Ports and encryption

Gorillaa SMTP supports three ports. All require TLS — plaintext connections are not accepted.

Port	Protocol	When to use
587	STARTTLS	Recommended. Connects in plaintext, then upgrades to TLS via the `STARTTLS` command. Supported by all modern clients.
465	Implicit TLS	TLS handshake happens immediately on connect. Use if your client prefers this mode.
2525	STARTTLS	Alternative port. Use if your ISP or hosting provider blocks port 587. Same behavior as 587.

All ports negotiate TLS 1.3 with AES-256-GCM encryption when supported by the client.

Authentication

SMTP authentication uses the AUTH LOGIN or AUTH PLAIN mechanisms:

Username: Always gorillaa
Password: Your full Gorillaa API key

The API key must have the email:send scope. Domain-scoped keys work too — SMTP enforces the same domain restrictions as the REST API.

Test mode keys

You can use grl_test_ keys via SMTP. The same test-mode limits and behavior apply as with the REST API (see Authentication → Test Mode).

SMTP vs REST API

Both methods produce identical results — same delivery pipeline, same tracking, same analytics. Choose based on your use case:

Feature	REST API	SMTP
Batch send	✅ Up to 100 per request	❌ One message per session
Scheduling	✅ `scheduledAt` parameter	❌ Not supported
Idempotency	✅ `idempotencyKey` parameter	❌ Not supported
Metadata & Tags	✅ Custom metadata and tags	❌ Not supported
Attachments	✅ Via API body	✅ Standard MIME attachments
Framework support	Requires HTTP client	✅ Built into most frameworks
No code changes	Requires integration code	✅ Config-only in many cases
Delivery tracking	✅ Full event tracking	✅ Full event tracking
Domain verification	✅ Same requirements	✅ Same requirements

Use the REST API when you need batch sending, scheduling, idempotency, or metadata. Use SMTP when your stack already has SMTP support and you want the simplest possible integration.

Troubleshooting

535 Authentication credentials invalid

Verify the username is exactly gorillaa (not your email address).
Verify the password is your full API key (starts with grl_live_ or grl_test_).
Check that the key has the email:send scope.
Check that the key hasn’t expired or been revoked.

Connection timeout

Confirm DNS resolves: nslookup smtp.gorillaa.one
Your network may block the port. Try port 2525 as an alternative.
Ensure your firewall allows outbound connections to smtp.gorillaa.one on the chosen port.

TLS handshake failure

Ensure your client supports TLS 1.2 or later.
If using port 587, make sure your client sends the STARTTLS command (most libraries do this automatically).
If using port 465, configure your client for implicit TLS (sometimes called “SSL”).

550 Domain not verified

The From address must use a domain you’ve verified in the dashboard.
Check domain status at Dashboard → Domains or via GET /v1/domains.
See the Domain Setup Guide for DNS configuration.

452 Too many recipients

SMTP allows up to 50 recipients per message (same as the REST API).
For larger sends, use the REST API’s batch endpoint or send multiple SMTP messages.

Verify connectivity

You can test SMTP connectivity with openssl:

# Test STARTTLS on port 587
openssl s_client -connect smtp.gorillaa.one:587 -starttls smtp

# Test implicit TLS on port 465
openssl s_client -connect smtp.gorillaa.one:465

A successful connection shows Protocol version: TLSv1.3 and Peer certificate: CN=smtp.gorillaa.one.

Get Started

Guides

Reference

Overview

SMTP server details

Quick start

Ports and encryption

Authentication

Test mode keys

SMTP vs REST API

Troubleshooting

Verify connectivity

​Overview

​SMTP server details

​Quick start

​Ports and encryption

​Authentication

​Test mode keys

​SMTP vs REST API

​Troubleshooting

​Verify connectivity

Overview

SMTP server details

Quick start

Ports and encryption

Authentication

Test mode keys

SMTP vs REST API

Troubleshooting

Verify connectivity