How to Set Up a Free SMTP Server: A Step-by-Step Guide

Eugene Suslov 15 Feb 2025

Creating an email account is fairly simple—you simply fill in some personal information on one of the main email providers (Gmail, Outlook, Yahoo, etc.), and voila, you’re good to go sending emails to whomever you want.

But what if you’re a business or solo professional sending hundreds or even thousands of emails daily? It should come as no surprise that the rules change.

Besides crafting effective emails and targeting relevant prospects, it’s equally crucial to consider the importance of proper business email setup and authentication, one of the most crucial of which is SMTP.

SMTP (Simple mail transfer protocol) is the mail delivery ‘engine’ that transfers your emails to your recipients’ inboxes, but it can get really complicated if you’re starting from scratch (and don’t have an IT pro by your side).

The good news? You can set up a free SMTP server with minimal effort and cost if you know what you’re doing, and this is exactly what this guide will walk you through.

What is an SMTP server?

SMTP (simple mail transfer protocol) is the fundamental technology behind delivering emails.

Think of it as a digital mail courier that picks up your message, transfers it to your recipient, and ensures that it reaches their inbox efficiently.

In oversimplified terms, here’s how the SMTP process works:

Your chosen email provider (Gmail, Outlook, or even an email outreach platform) connects to the SMTP server to establish an email client connection.
The SMTP server authenticates your information and verifies that you are an authorized sender, which also helps you prevent future spam and phishing attempts.
Once you’re all set up, the SMTP server will process each email and check the DNS (domain name system) to find your recipient’s mail server.

Finally, the SMTP server transfers the email to the recipient’s mail server, which then places it in the appropriate inbox or filters it as spam based on security policies, among other email deliverability factors.

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Why is an SMTP server essential?

An SMTP server does much more than simply facilitate the transfer of emails—it plays a crucial role in successful email deliverability, especially in the context of mass email sales or marketing campaigns.

Without a properly configured SMTP server, your sales or marketing emails may simply fail to reach your customers resulting in lost opportunities and increased spam rates.

Here’s a quick overview of why an SMTP server is essential for all businesses:

Reliable email deliverability → ensures your emails reach recipients’ inboxes instead of getting blocked by spam filters set in place to protect users, which also builds and maintains a strong IP sender reputation, creating a snowball effect;
Bulk email sending → whether it’s a marketing newsletter or a sales outreach campaign, SMTP servers are the only way to handle mass email volumes, unlike standard email clients that have sending limits;
Faster and more efficient → ensures emails are processed and delivered without delays, making it ideal for businesses that rely on time-sensitive email communications such as transactional notifications, appointment reminders, etc.;
Security & authentication → SMTP servers use encryption protocols to protect email content, as well as authentication methods like SPF, DKIM, and DMARC to protect your email from any cyber threats;

In summary, whether you’re running email marketing campaigns, sending automated transactional emails, or ensuring smooth internal communication, a properly configured SMTP server is vital. Investing in a high-quality SMTP solution helps safeguard email security, enhances deliverability, and supports business scalability.

Free SMTP vs paid SMTP services

Chances are, you’re looking to set up a free SMTP server, and just to be clear—there are many free options out there.

Now, whether a free SMTP server has everything you need to meet your business needs is another question, because there are also the more premium paid services. Let’s break it down:

Before setting up an SMTP server, it’s crucial to determine whether a free SMTP service will meet your business needs or if investing in a paid option is the better choice. The right decision depends on your email volume, security requirements, and the level of reliability you expect.

Free SMTP servers:

Free SMTP services are a great starting point for individual professionals and small businesses that only need basic email-sending features to satisfy their low-volume outreach needs.

Besides being free and more than sufficient for low-volume senders, free SMTP servers are also quicker and easier to set up and operate, even in the context of business email correspondence.

However, bear in mind that the vast majority have sending limits (daily or monthly) which can definitely hinder scalability. For instance, Gmail’s free SMTP service allows only 500 emails per day, so if your marketing newsletter has more contacts—this already wouldn’t work.
At the same time, free SMTP servers are shared among many users, who as a result may experience lower deliverability rates and less advanced security features.

Paid SMTP servers:

On the other hand, if your business is involved in mass email campaigns for its sales and marketing efforts, a paid SMTP service is probably the better option. Here’s why the upgrade makes more sense for growing businesses:

Paid SMTP providers don’t cap email-sending volumes like free alternatives, accommodating growing businesses that send thousands or millions of emails monthly.
Paid SMTP servers use dedicated IPs, top-notch authentication protocols (SPF, DKIM, DMARC), and premium email deliverability tools to ensure your emails land in inboxes rather than spam folders.
Premium SMTP services offer real-time insights into users’ open rates, bounce rates, and click-through rates, allowing businesses to optimize email campaigns and troubleshoot any delivery issues.
Paid providers provide enhanced security features (encryption, two-factor authentication, and legal compliance), ensuring that all sensitive business data remains protected at all times.

The better SMTP server alternative—API

Setting up an SMTP server will take some effort—we’ll cover the steps shortly, but before we do, it’s worth mentioning that there is a more advanced piece of tech out there for sending mass emails, and that is API.

APIs (application programmable interface) are a more modern and versatile email transmission method that operates directly through an email service provider while allowing multiple software to communicate with each other.

To better understand this tech, let’s explore the example with Reply’s email API.

With just a few lines of code (and some minor IT support), businesses can integrate Reply’s powerful email outreach capabilities into their existing tools, allowing them to send bulk emails via HTTP requests rather than SMTP, offering more flexibility, speed, and additional features.

For starters, once the API is set up—Reply.io automatically handles all email authentication and deliverability optimization, empowering businesses to simply focus on their email campaigns rather than the technical elements of outreach.

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Moreover, Reply.io offers real-time email authentication and spam monitoring, making sure that businesses maintain a strong sender reputation, stay above spam thresholds, and are compliant at all times.

If you’re wondering what performs better for mass email campaigns, API vs SMTP—take a look:

All in all, finding a super functional server SMTP free of charge with no sending limits is impossible, but if your outreach needs are low-scale—you’ll be just fine with a free one.

If on the other hand, you’re a growing business with huge email campaigns, you’ll most likely need to upgrade to a paid SMTP server or consider an email outreach API like described above.

How to set up a free SMTP Server

Let’s get back to the main issue at hand—how to set up a free SMTP server, step by step.

In practice, if you follow the following steps, you’re likely to get it up and running in no time without running into any problems, especially since all the SMTP services and tools do their best to make it straightforward for their users.

Let’s get started.

Gear up with a free SMTP tool

The first step is undoubtedly selecting the right SMTP provider. There are several free SMTP solutions that allow businesses to send emails without additional costs while ensuring proper email authentication, spam filtering, and delivery tracking.

The majority of them, however, offer free SMTP services up to a certain limit. Another thing to keep in mind is that each SMTP provider has different features. For instance, one may have bigger sending limits while another will offer enhanced deliverability rates, so it’s up to you to decide which is more important.

Here are three of the best SMTP providers with free plans, each offering unique advantages:

Gmail SMTP

Google offers a free SMTP server that allows Gmail and Google Workspace users to reliably send emails to users of all servers. Unsurprisingly, it’s the most widely used free SMTP service due to its credibility and ease of setup, and perhaps being Gmail’s native server also helps.

The free plan has a limit of 500 emails per day for Gmail accounts and 2,000 emails per day for Google Workspace users, with a whopping reported average of over 98% inbox placement rate for properly authenticated emails.

With its native TLS encryption, seamless integration capabilities with third-party apps, and Google’s spam filtering, Gmail’s free SMTP solution is ideal for small businesses and solopreneurs.

How to access Gmail’s SMTP server:

SMTP Server: smtp.gmail.com
Port: 587 (TLS) or 465 (SSL)
Authentication: required (use your Gmail credentials or an App Password for third-party applications).

Brevo (formerly Sendinblue)

Brevo is much more than an SMTP provider—it’s an established email marketing service with its own SMTP server designed for small and medium-sized businesses.

The free plan has a sending limit slightly lower than Gmail’s—up to 300 emails per day, which as you can imagine, is not nearly enough for growing businesses with huge email lists.

The average reported inbox placement rate is a staggering 96%, given all the authentication protocols are properly configured, so it’s definitely a reliable SMTP provider.

Besides offering a free SMTP server, Brevo also provides an SMTP relay (more on that shortly), email tracking, detailed analytics, and other marketing automation features like SMS campaigns and sender reputation management, should you need them. Therefore, this is an ideal solution for those looking for an all-in-one email marketing and transactional email solution.

Amazon SES

Amazon SES is another great SMTP provider for businesses. It’s a cloud-based service designed to facilitate scalability and higher email volumes, with a quite generous free plan—up to 62,000 emails per month.

Their reported inbox placement rate is the same as Gmail’s—98%, probably thanks to Amazon’s strong sender reputation and dedicated IP options.

With real-time email tracking, advanced authentication settings, and a native integration with AWS, it’s the absolute best SMTP provider for professionals and businesses already or planning on using AWS.

A pretty cool recent Amazon SES addition is its AI-powered email filtering feature that further helps to prevent bounce and spam rates for its users.

Configure your email client

Now that you’ve chosen your desired provider, the first thing you should do is sign up for their service and get your SMTP credentials, including:

SMTP server address
Port number
Username (often your email address)
Password or API key for authentication

Once you have your SMTP credentials, the next step is to configure your email client or server to ensure proper email sending. Whether you are using Outlook, Gmail, Yahoo, or a third-party sales or marketing automation platform, the setup process generally follows the same structure:

Access your email settings → open your email client or application settings and locate the ‘Outgoing Mail Server (SMTP)’ section.
Enter your SMTP server address → input the SMTP server address provided by your SMTP service provider. (e.g., smtp.gmail.com for Gmail or smtp.brevo.com for Brevo).
Specify the SMTP port number:
- Use 587 for TLS encryption (recommended for most providers).
- Use 465 for SSL encryption (more secure but less commonly used).
Enter your SMTP username and password → this will usually be your email address or a dedicated API key provided by the SMTP service.
Enable authentication → ensure that the SMTP authentication option is enabled, as most email providers will reject unauthenticated emails to prevent spam for their users.

And there you have it. Now it’s just time to save your settings and send out a test email to confirm that everything runs smoothly, without any deliverability issues.

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Set up your free SMTP relay

An SMTP relay is what forwards your emails to other third-party servers and ensures they reach the recipient’s inbox. Think of SMTP relay as the postman who picks up an email from your SMTP server (the post office), and delivers it to other recipients in other servers to prevent emails from getting blocked, delayed, or marked as spam.

The major SMTP providers like the three we mentioned offer native free SMTP relay services, so you wouldn’t need to worry about this as they would handle the relays on your behalf.

However, if your SMTP provider doesn’t include a built-in relay, consider using one of the leading free standalone SMTP relay services like Postmark, Mailgun, and SMTP2GO.

Get a free SMTP host for testing

Before going live and launching those email campaigns, it’s absolutely crucial to first test your SMTP setup to make sure everything is running smoothly and avoid issues like emails landing in spam or incorrect server settings.

This is why we highly suggest finding a free SMTP host for testing your emails. Think of these services as a sandbox environment where you can analyze all deliverability errors and authentication issues without sending any real emails to customers.

Some great free SMTP host services for testing include:

Mailtrap – simulates email sending, and provides a virtual inbox for error detection and spam testing;
SMTP2GO – offers real-time email tracking, SMTP logs, and advanced analytics;
G Suite SMTP Relay – ideal for businesses using Google Workspace that wish to keep everything under one roof.

The testing process is fairly simple—input your SMTP credentials to set up the test email client and send your test email. Right away, you will get a detailed deliverability report and spam score analysis. You can use this report to configure authentication settings, review SMTP logs, and troubleshoot other potential issues.

Doing this before launching large-scale email campaigns can save tons of time, effort, and missed opportunities.

Authenticate your email account & monitor performance

Last but not least, once your SMTP server is set up and running, it’s equally important to set up the three holy grails of email authentication—SPF, DKIM, and DMARC, and then consistently monitor them all.

Your SMTP server will facilitate the delivery of your emails, but it’s the SPF, DKIM, and DMARC authentication protocols that will determine whether they reach your recipients’ inboxes or get rejected by their mail servers and sent to spam. They’re also crucial for your own email security, which is extra important for businesses dealing with sensitive customer and financial information.

Once again, you can turn to dedicated online tools like MailTester to audit your email authentication settings.

However, if you’re looking to streamline all your email activities under one roof, including setting up and monitoring SMTP servers and SPF, DKIM, and DMARC authentication settings—the top email outreach platforms like Reply.io will be your best bet. For instance, Reply.io monitors all your email account settings in real-time and provides actionable alerts if something goes wrong:

In any case, email deliverability is a crucial factor in successful business outreach, so whether it’s manually monitoring all your email settings or leveraging an outreach tool—make sure to keep your hand on the pulse.

At the same time, make sure to follow all the email deliverability best practices to maintain a strong business IP reputation, avoid spam folders, and ensure all your emails reach their intended recipients.

Scale your email outreach safely

Manually setting up a free SMTP server may seem quite complex at first glance, but the good news is that once it’s up and running—you’re good to start your mass marketing and sales email campaigns. Just make sure to keep an eye on the status of your SMTP server from time to time to ensure everything is running smoothly.

Without proper SMTP settings, you run the risk of harming your business’s sender reputation and seeing fewer emails reach their designated inboxes.

For businesses wishing to skip this tedious process altogether, consider using an email outreach tool like Reply.io to combine powerful email automation with AI personalization, with native and automated email authentication setup and monitoring.

If you’re not in the market for an outreach tool, perhaps consider one of the leading email outreach APIs like Reply’s API to integrate email capabilities into your digital stack.

In any case, you will have 100% confidence that your email account is properly configured and authenticated while all your emails are being delivered to your recipients like clockwork, which means all you have to do is focus on making those emails as impactful as possible.