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Free open SMTP relay for your emails

Send emails through a free open SMTP relay and avoid the cost and hassle of building and maintaining your own SMTP server. Mailgun’s flexible and powerful SMTP service has you covered.

Using free open SMTP relay for sending bulk emails

Setting up your own SMTP server to send mail can be a time-intensive and complicated affair. Not only are there security issues to contend with, but email deliverability can be a major challenge. That’s because most email providers have very high spam detection barriers in place, and any email sent from a custom SMTP server has a high likelihood of getting snagged by one of those filters.

Enter SMTP relay. A mail relay is an easy and effective way to solve for spam and security issues inherent with outgoing mail servers. You simply route your outgoing email to a professionally managed SMTP server, and that third-party sends those outgoing emails on your behalf. Open relay means the SMTP server is routing both messages from external sources and internal server mail, while closed relay only routes messages generated on the internal network or server. By its nature, open mail relay is more expansive, but it can also be more vulnerable to spam abuse.

With SMTP relay, your personal email address like your gmail account is irrelevant. Whether you’re using Google’s Gmail, Yahoo, AOL, or a custom domain for your email address, you can route your messages through a third-party mail server and dramatically increase the odds of your email marketing actually reaching customers without hitting daily rate limits and other barriers. In short, mail relay lets you use whatever email you want without the hassles of building or managing your own SMTP server.

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SMTP relay server in action

While it’s costly to build and maintain your own SMTP server, there’s an abundance of free SMTP options out there. Mailgun offers a flexible and powerful SMTP service.

What some users don’t realize is how dynamic that free SMTP server can be behind the scenes. When you’re sending outgoing mail in bulk, for instance, the SMTP server doesn’t simply push through all of those outgoing emails at once. Instead, Mailgun automatically queues which emails should be sent to each email client, based on factors like Gmail’s or Yahoo’s receiving guidelines and maximum send limits. That means fewer outbound emails are blocked by email service providers, and more of your mail reaches its intended target.

Mailgun’s queueing algorithms aren’t static, either. As your reputation grows and IP addresses are warmed up, the queue dynamically adjusts your send rates.

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Setting up SMTP relay

One of the best things about a SMTP relay service is how easy it is to set up, whether you’re working with a WordPress site or a custom domain. With Mailgun, you simply add and verify your domain name, choose between a dedicated or shared IP address, and then set up your SMTP relay server. Add your username, password, SMTP server host name, and SMTP port into your application’s configuration settings, and you’re ready to start sending. If you want another layer of security to your email, you can also add a regular or SSL connection, depending on which port you use.

Email marketing can be a complicated endeavor—and making sure your messages clear your outgoing server and land in your customers’ Gmail, AOL, or Yahoo inboxes shouldn’t be a daily concern. Taking advantage of a free SMTP relay with a Mailgun email account can spare you the worry—while saving you time and money.

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Try out Mailgun and integrate SMTP services with your app in minutes to increase your email delivery rates.

Check out our plans to bundle together features for better deliverability. For businesses that send over 100,000 emails.

Other features

Explore beyond SMTP

Mailgun has a variety of features for companies in need of a free open SMTP relay.

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