Fast, secure, reliable SMTP Relay Service

MailerSend’s SMTP relay service empowers you to send transactional emails quickly and at scale. Optimized for maximum deliverability so there’s no need to manage your own SMTP server.


Get 3,000 emails/month free

Start out with our free plan and get 3,000 emails, award-winning support, and standard features. Need more emails? Pay as you go or upgrade for better pricing and premium features.


Quick and simple setup

Send emails from any app, device or email client with just an SMTP server name, port, username and password—no need for complex coding. A user-friendly interface allows you to manage domains and users with ease.


Plug & play with WordPress

Use MailerSend’s WordPress SMTP plugin to quickly connect your account and start reliably sending high volumes of transactional email from your WordPress site.


Enjoy better email deliverability

Reach the inbox with a third-party SMTP service that provides clean IP addresses and authenticated domain names. Sender reputation and blocklisting is managed and monitored by our deliverability experts.

Award-winning customer support

Whether you need help getting started with MailerSend’s SMTP service, want advice about advanced features or troubleshooting your account, our friendly customer service team is available 24/7 and just a click away.

93% satisfaction rate
100% response rate
24/7 support hours

Reach more inboxes, faster

In transactional email sending, speed and delivery are everything. With MailerSend’s SMTP server, important messages will get where they need to in a timely manner, while increased inbox placement ensures a better customer experience.


Send important emails securely

Our robust and secure sending infrastructure utilizes SPF and DKIM protocols to authenticate your emails, while the IP allowlist enables you to safeguard your account against unauthorized use.


Create up to 5 SMTP users for each domain

Effortlessly scale your transactional email with multiple sets of SMTP credentials for every domain. Keep SMTP users organized with customizable names and pause, enable and delete as needed.


Easily manage multiple domains

Use one intuitive dashboard to manage all of your brands or clients without mixing up templates or settings. Keep everything secure with separate access to individual domains.


Easily connect other web apps with MailerSend so they seamlessly work together to share information, automate workflows and enhance your customer experience.

Stay informed with reports

Track email events in real-time on your dashboard and view separate analytics for multiple domains. View activity statuses such as bounces, clicks and unsubscribes and filter your email messages further by subject, recipient and tags.

Enhanced sending functionality with email API

Easily add email to your stack with 7 official libraries and extensive API documentation. Get advanced functionality such as templates, inbound routing, personalization and more.
Read our API docs
curl -X POST \
https://api.mailersend.com/v1/email \
    -H 'Content-Type: application/json' \
    -H 'X-Requested-With: XMLHttpRequest' \
    -H 'Authorization: Bearer {place your token here without brackets}' \
    -d '{
        "from": {
            "email": "your@email.com"
            "to": [
            "email": "your@client.com"
        "subject": "Hello from MailerSend!",
        "text": "Greetings from the team, you got this message through MailerSend.",
        "html": "

Greetings from the team, you got this message through MailerSend.

" }'
use MailerSend\MailerSend;
use MailerSend\Helpers\Builder\Recipient;
use MailerSend\Helpers\Builder\EmailParams;

$mailersend = new MailerSend(['api_key' => 'key']);

$recipients = [
new Recipient('your@client.com', 'Your Client'),

$emailParams = (new EmailParams())
->setFromName('Your Name')

Greetings from the team, you got this message through MailerSend.

') ->setText('Greetings from the team, you got this message through MailerSend.'); $mailersend->email->send($emailParams);
const Recipient = require("mailersend").Recipient;
const EmailParams = require("mailersend").EmailParams;
const MailerSend = require("mailersend");

const mailersend = new MailerSend({
    api_key: "key",

const recipients = [new Recipient("your@client.com", "Your Client")];

const emailParams = new EmailParams()
    .setFromName("Your Name")

Greetings from the team, you got this message through MailerSend.

") .setText("Greetings from the team, you got this message through MailerSend."); mailersend.send(emailParams);
package main

import (


var APIKey string = "Api Key Here"

func main() {
    ms := mailersend.NewMailersend(APIKey)

    ctx := context.Background()
    ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
    defer cancel()

    subject := "Subject"
    text := "Greetings from the team, you got this message through MailerSend."
    html := "

Greetings from the team, you got this message through MailerSend.

" from := mailersend.From{ Name: "Your Name", Email: "your@email.com", } recipients := []mailersend.Recipient{ { Name: "Your Client", Email: "your@client.com", }, } variables := []mailersend.Variables{ { Email: "your@client.com", Substitutions: []mailersend.Substitution{ { Var: "foo", Value: "bar", }, }, }, } tags := []string{"foo", "bar"} message := ms.NewMessage() message.SetFrom(from) message.SetRecipients(recipients) message.SetSubject(subject) message.SetHTML(html) message.SetText(text) message.SetSubstitutions(variables) message.SetTags(tags) res, _ := ms.Send(ctx, message) fmt.Printf(res.Header.Get("X-Message-Id")) }
from mailersend import emails

mailer = emails.NewEmail()

mail_body = {}

mail_from = {
    "name": "Your Name",
    "email": "your@domain.com",

recipients = [
        "name": "Your Client",
        "email": "your@client.com",

mailer.set_mail_from(mail_from, mail_body)
mailer.set_mail_to(recipients, mail_body)
mailer.set_subject("Hello!", mail_body)

Greetings from the team, you got this message through MailerSend.

", mail_body) mailer.set_plaintext_content("Greetings from the team, you got this message through MailerSend.", mail_body) mailer.send(mail_body)
require "mailersend-ruby"

# Intialize the email class
ms_email = Mailersend::Email.new

# Add parameters
ms_email.add_recipients("email" => "your@client.com", "name" => "Your Client")
ms_email.add_recipients("email" => "your@client.com", "name" => "Your Client")
ms_email.add_from("email" => "your@domain.com", "name" => "Your Name")
ms_email.add_text("Greetings from the team, you got this message through MailerSend.")
ms_email.add_html("Greetings from the team, you got this message through MailerSend.")

# Send the email

Reach more customers with transactional SMS

Improve the customer experience and enjoy even higher open rates by sending important updates directly to recipient’s phone numbers with the transactional SMS API.

Don’t just take our word for it.
Here’s what our customers think

Solved a major headache

"Very easy to set up—integrating with Joomla was flawless, test emails were being sent within a few minutes. Generous free allocation—no reason to use Google's standard workspace SMTP servers."

G2 user

Great SMTP relay service

"Integration with our business was easy using their SMTP service. Their support is the best. Usually they answer within 1 hour and the information provided is very detailed and helpful."

Pablo V.

Great product for a great price

"Very easy to use. I compared it with several other bulk email services and MailerSend offers the most value for the cost. Very happy to have found this product and I will be using it long-term."

Brennan S.

Frequently Asked Questions

What is SMTP relay service?

Simple Mail Transfer Protocol (SMTP) is a widely supported standard for exchanging information between servers (i.e. sending email). 

SMTP service providers enable businesses to utilize SMTP without the need to manage their own servers. It allows senders to deliver bulk or transactional email through a trusted third-party.

How does MailerSend make my email sendings secure?

MailerSend’s SMTP server is built on a powerful and secure email infrastructure. Our mail servers protect your email sendings with SPF, DKIM and DMARC security protocols, so you can always be confident that your sending domain is safe from unauthorized sendings and your sender reputation remains intact.

How do I set up SMTP?

Simply sign up to MailerSend for free and configure your account. Once you're approved and you have completed domain verification, you can test out MailerSend with 100 free emails. Then, choose a Free or Premium plan to get more emails, features and to start sending!

We have comprehensive documentation to help you get started, and our customer support team is available 24/7 to assist you.

What support will I receive if I encounter an issue?

MailerSend is renowned for its excellent support so you can rest assured that your transactional emailing is in good hands. If you need help getting set up, have questions about any of our features, or have any issues with your account, you’ll get a quick and friendly response from our 24/7 customer support team.

What options do you provide for developers?

We know that every developer is different, that’s why we offer 7 SDK libraries that are updated monthly, so you can choose your favorite language to work with. Developers can simply plug in our API or SMTP relay and MailerSend will do the rest, while low-coders can use our extensive library of integrations to connect their apps.

Check out our developers documentation.

Can I get a dedicated IP address?

MailerSend offers dedicated IPs for high-volume senders. If you’d like to learn more about whether a dedicated IP is right for your business, get in touch!

How much does an SMTP service cost?

MailerSend offers a fair and transparent pricing policy, with no hidden costs and a pay-as-you-go model.  

You can get started with our free plan which includes 3,000 emails/month, with additional emails charged on a pay-as-you-go basis at a rate of $1.00/1,000. 

If you need more emails or advanced features, our cost-effective Premium plan is available for up to 2,500,000 emails/month, with additional emails charged at decremental rates starting at $0.90/1,000. Need more than 2,500,000 emails? Talk to us about a custom Enterprise plan.

More features to explore

MailerSend is packed full of features that help you save time and grow your business.

Integrate emails in your stack now

Try MailerSend's SMTP email service in minutes with a free trial domain. Add your domain and start sending to customers with 3,000 free emails per month.