January 24, 2023

7 Best SMTP Servers for Email Marketers (2023)

Reading time about 13 min

High email deliverability, bulk email sending, increased security  — if that sounds like what you’re looking for, you need a SMTP server.

High-volume email senders need something more reliable than a basic email marketing platform. SMTP service providers enable you to send bulk email campaigns and transactional messages at high speed, without having to worry about deliverability issues. 

We’ve reviewed the best SMTP service providers for high-volume sending and transactional emails here. Read on to find the best service provider for your company.

What the Best SMTP Servers Do

A Simple Mail Transfer Protocol (SMTP) server is an application that sends emails from senders’ to recipients’ email servers. Simply put, SMTP transfers emails across the internet. 

There are regular SMTP servers, like Gmail or Outlook, and dedicated SMTP relay servers, like Brevo (formerly Sendinblue). While Gmail is good for sending personal emails and one-on-one business messages, sending bulk email campaigns and transactional emails is best with a dedicated SMTP relay server

So how do SMTP servers work? 

Without going too deep into the technical details, here’s what happens when you send a business email through an SMTP server:

  1. Your Mail User Agent, or mail client, connects to your SMTP server.
  2. The mail client communicates with the SMTP server and gets all the necessary information about the sender and recipient.
  3. The Mail Delivery Agent takes the message information and sends it in a proper format to the receiving mail client.
  4. The message reaches the receiving Mail Delivery Agent’s inbox.

The Top SMTP Servers at a Glance

Choosing an SMTP Server

How do you choose the right SMTP server as a non-tech specialist? Actually, you don’t have to be tech-savvy to choose and successfully use an SMTP relay server for your campaigns. You just need to be aware of the following factors.

Deliverability rate

High deliverability is the number one reason why anyone uses an SMTP server. The SMTP technology ensures better deliverability than regular marketing campaigns. 

So check reviews to make sure users don’t report deliverability issues. Then, send a few trial campaigns and use a deliverability testing tool to measure it yourself.

Sender reputation

Without a solid sender reputation, you can’t expect high deliverability from an SMTP server. It’s important that your SMTP relay server provides all the necessary tools for maintaining your sending IP address and helps you avoid recipients’ spam folders. 

A proper SMTP server requires new account validation, enables domain name authentication, and follows email authentication protocols (SPF, DKIM, and DMARC).

Log retention

Retention logs are the metrics of the campaigns you send. It’s best that your SMTP email service retains logs for as long as possible. This way, you can always go back and check them if issues arise. 

Most SMTP servers have a 30-day retention period. Some apps, like Brevo, allow for unlimited log retention, enabling users to configure their retention period by themselves.

Ease of use

An SMTP server should be easily accessible by non-tech marketers and business owners as well as tech-savvy developers. It’s supposed to simplify the process of email sending, not overcomplicate it. 

A user-friendly interface, responsive support, and proper onboarding are among the key features you should be looking for in your SMTP server.

Are There Free SMTP Servers?

Some SMTP servers are available for free. On this list, only Brevo and SendGrid offer free SMTP relay services.

7 Best SMTP Servers

We’ve compiled a list of the best SMTP service providers that help businesses to send large volumes of emails without roadblocks.

1. Brevo (formerly Sendinblue)

“Needed an professional SMTP supplier with good delivery rate. Brevo is that perfect solution!” Review on G2

Marketing email workflow for a signup button on a website.

Brevo has a dedicated transactional email service called Brevo SMTP. It lets you send the whole range of transactional emails:

  • Signup confirmations
  • Order confirmation emails
  • Password recovery emails
  • Payment confirmation emails
  • Bulk emails

Brevo has an established sender reputation among email clients, including Gmail and Outlook. It’s introduced all the necessary procedures to help you maintain your sender IP reputation. With Brevo’s SMTP server, you don’t have to worry about the deliverability of your emails.

On our Transactional Emails plan you get:

  • RESTful APIs, SMTP, webhooks
  • Email tracking and unlimited log retention
  • Dynamic templates for personalization
  • Drag-and-drop editor and a template gallery
  • Dedicated IPs
Email API showing a confirmation transactional email for a purchase on a website.

Brevo SMTP pros

  • Full control: Access dedicated IPs for high-volume senders. 
  • Sender reputation: Split transactional and promotional emails by sender or IP address.
  • Automation: Build automation workflows based on user activity and website behavior for email and SMS marketing.
  • Unlimited log retention: Access logs and previews with no time limit.
  • Unlimited contacts: You don’t have to pay for the size of your email list.
  • Functionality: Brevo is more than an SMTP service — it’s an all-in-one marketing automation platform for growing businesses with capabilities for lead capture, email templates, A/B testing functionality, a drag-and-drop email editor, and other critical features for email marketers.
  • Integrations for ecommerce: Use custom-built email plugins for WordPress sites and ecommerce platforms to promptly send notifications and updates.

Brevo SMTP cons

If you’re looking for an SMTP server without many bells and whistles, you might want to choose a more basic solution.

Brevo SMTP pricing

Brevo offers a free SMTP server. You can send up to 300 transactional emails and marketing messages per day without paying a cent. Paid plans for the transactional service only start at $15/month and include 20,000 emails per month with no daily sending limit. The marketing suite including both transactional and marketing emails starts at $25 for 20,000 emails a month.

2. Amazon SES

SMTP server tool

Amazon Simple Email Service (SES) is a transactional and bulk email sending service. It allows developers to build email functionality into any application. It’s particularly good for companies that run applications on Amazon Web Service (AWS).

Amazon SES pros

  • Dedicated IP addresses: Request a dedicated IP address to manage your own IP reputation.
  • Reputation & deliverability dashboards: You can track issues impacting your reputation and delivery rates across two dashboards.
  • Mailbox Simulator: Run tests to see how your application handles different scenarios, such as bounces, unsubscribes, or complaints, without making a real impact on your sender reputation.
  • Affordable: Amazon SES doesn’t include typical marketing automation features, and therefore, the service is very cheap.

Amazon SES cons

  • The implementation process requires a lot of manual work.
  • Steep learning curve for non-tech users to set up and use Amazon SES.

Amazon SES pricing

Amazon Simple Email Service (SES) offers a pay-as-you-go model, where you’re charged based on the number of emails sent and received. You can expect to pay $0.10 for every 1,000 emails. No subscription is needed. 

3. SendGrid

SMTP tool

SendGrid is a cloud-based transactional and marketing email delivery service. It provides an SMTP service for reliable delivery and scalability.

SendGrid pros

  • Reputation and delivery monitoring: Get insights into your sender reputation, delivery rates, and engagement analytics.
  • Real-time email analytics: Access real-time performance data in your personal dashboard or via API.
  • Documentation: The setup process is made easier with comprehensive documentation, open source libraries, and a clear setup flow. 
  • Segmentation: Segment email and SMS audiences alike.

SendGrid cons

  • After-sale support: Users report that the SendGrid support team isn’t very helpful when you sign up.
  • Pricing: Since being acquired by Twilio, SendGrid got more expensive. 

SendGrid pricing

SendGri’s SMTP service is free for up to 100 emails/day. Along with SMTP relay, APIs and webhooks are also available on the free plan. To access more email credits, you can upgrade to a paid plan starting at $19.95/month for up to 50,000 monthly emails. 

Related: 5 Best SendGrid Alternatives for Transactional Email

4. Mailgun

SMTP server provider

Mailgun is an email service offering a set of powerful APIs for sending, receiving, and tracking emails. Known as a transactional email service “built for developers, by developers,” Mailgun has comprehensive API documentation and an easy SMTP integration.

Mailgun pros

  • Reliability: Mailgun is one of the most reliable services on the list.
  • Dedicated mail server: Send both marketing campaigns and transactional emails alike.
  • Real-time reporting: Access hourly data on your email performance.
  • Enterprise-focused solutions: Create a custom enterprise-grade solution for sending emails at scale.

Mailgun cons

  • Mailgun is built for developers. It’s not designed for non-tech teams. It’s a tech cloud-based SMTP service by Mailjet’s parent company Sinch.
  • On cheaper plans, the log retention period is only five days, and the minimum message retention period is one day.

Mailgun pricing

Mailgun doesn’t offer a forever-free plan. A free trial lasts for 30 days and includes 5,000 free emails. Email APIs, SMTP Relay, and webhooks can be accessed during a free trial and are included in every paid plan. Mailgun’s pricing plans at $35/month.

Read more: 7 Best Mailgun Alternatives For Transactional Emails

5. Postmark

SMTP server tool

Postmark is ActiveCampaign’s email service built for developers and product teams. The platform offers a simple but quality SMTP relay service for sending transactional email.

Postmark pros

  • Deliverability: Postmark has a narrow focus on deliverability, which means your transactional emails will most likely always be reaching recipients’ inboxes.
  • Control: Promotional campaigns and transactional emails are sent through separate sending infrastructure.
  • Documentation: Postmark offers concise documentation, making it easy to start sending emails using SMTP.
  • Message retention: Access email previews and recipient information within a 45-day window.

Postmark cons

Functionality: If you’re looking for an all-in-one marketing platform, Postmark won’t fit your needs.

Postmark pricing

Postmark doesn’t offer traditional packages and pricing tiers. You simply pay for email credits and access all the features, starting from $15-month for 10,000 emails. However, to get a dedicated IP address, you’ll need to purchase an add-on for $50/month.

6. Mailchimp (Mandrill)


Mailchimp Transactional Email (formerly Mandrill) is Mailchimp’s add-on providing SMTP and transactional email services. 

Mailchimp pros

  • Functionality: If you need a comprehensive marketing automation solution, Mailchimp might be a good (but pricey) option, and the add-on makes sense.
  • Email tracking: The platform lets you track the key metrics, like deliverability rates, bounce issues, click rates, and other stats.
  • Deliverability: Similar to other SMTP servers, Mailchimp Transactional Email has no problems with email delivery.

Mailchimp cons

Pricing: to access the SMTP service, you’ll need to pay for Mailchimp’s email marketing functionality and buy transactional email credits as an add-on.

Mailchimp pricing

Mailchimp has a forever-free plan with a monthly sending limit of 1,000 emails and limited features. To access Mailchimp Transactional Email, you need to upgrade to the paid Mailchimp marketing plan and purchase transactional email credits. New users can send up to 500 transactional emails for free. 

Find out more: Best Mailchimp Alternatives Compared

7. SparkPost


SparkPost is a heavy-duty SMTP server. It’s more of a B2B, email-for-email companies software, used for large volumes of bulk emails.

SparkPost pros

  • Handles huge volumes: Probably the biggest bulk sender
  • Reliability: Great uptime of 99.99%
  • Trustworthy: Big names from many industries rely on its technology

SparkPost cons

  • For big players only: Small businesses may feel underappreciated by a service that handles such large clients
  • Too complex: As a tech-focused platform, SparkPost can be overwhelming for non-tech users.
  • Coding skills needed: You need to code your emails as there’s no drag-and-drop email editor.

SparkPost pricing

SparkPost does offer free SMTP test accounts with limited sending volumes. Plans start at $20/month for 50,000 emails and next tier at $75 with premium features.

How to Choose the Right SMTP Server?

What are you looking for in your SMTP server? Do you want it to be a comprehensive marketing automation solution? Do you simply need an add-on to connect with your current email marketing platform? If you’re seeking marketing automation software with SMTP relay service, try out Brevo SMTP. 

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