Transactional Email Best Practices – Using SMTP


    One of the most frequent concerns we hear when onboarding new clients are the fear their website transactional emails may be going to SPAM or otherwise not delivered properly. These emails might be contact form notifications meant for a sales manager, and this communication from potential customers can mean losing income to our clients. Email deliverability is critical, therefore we wanted to help with these transactional email best practices.

    Customer emails could include a purchase receipt or follow-up instructions after signing up for a digital course. When customers expect a purchase receipt but don’t see it immediately in their inbox (because it ended up in SPAM folders or retained in quarantine), they may lose trust in our abilities, damaging future associations.

    Wait, what are transactional emails?

    Transactional emails are different from marketing emails. Transactional emails are sent automatically and instantly following a specific action or event on your website. Examples can include:

    • Password reset emails and account notifications
    • Subscription confirmation (or double opt-in email)
    • Order confirmation email
    • Shipping confirmation email
    • Delivery confirmation email
    • Notification emails (delivery updates, new messages, etc.)
    • Bills, receipts, etc.

    With email, no one can guarantee 100% deliverability 100% of the time. There are literally hundreds of different email clients, with thousands of unique configurations, and each end-user may have filtering systems set up beyond our reach.

    Fortunately, we use four standard tools to increase the likelihood that these emails will reach their intended destination, which works most of the time.

    These tools/concepts are as follows:

    • SMTP (Simple Mail Transfer Protocol)
    • SPF (Sender Policy Framework)
    • DKIM (DomainKeys Identified Mail)
    • Understanding SPAM filters
    • bonus: DMARC (Domain-based Message Authentication, Reporting & Conformance)

    Diagnosing what triggered the issue starts by reproducing it, preferably in an environment under your own control. Therefore, if your customer says your emails end up in SPAM, try sending the same email to your inbox.

    You can look at the email headers for clues to help you determine which of those main tools to focus on first. In Gmail or Google workspace, these links are located in the upper right-hand corner of each message under the three verticle dots. Under this menu, click on the “show original” link. Compare the following screenshots to your inbox.

    Transactional email best practices. Using SMTP to improve deliverability.

    If your email services are on the same server as your web hosting, you probably need to work on updating your SPF and DKIM records in your DNS. More to come on that subject soon. But for now, it is possible another mischievous customer has been sending too many spam emails from that same IP address, and the IP address has gotten blacklisted.

    If your hosting and email services are separate, then read on.

    Using SMTP to Improve Transactional Email Deliverability

    One of the most common situations among our clients is they have their regular email services provided by a trustworthy company, such as Google Workspace. Overall, Google is generally a far superior email service than the native email hosting that often comes bundled with web hosting. As such, this is one of our favorite transactional email best practices and we recommend it to our own clients.

    However, a consequence of this is that your website is trying to send out emails through email scripts on your server, but there is a disconnect since the MX records point elsewhere.

    When an email provider (like Google, Outlook, etc.) receives a new email, they will verify authentication to ensure it is legitimate. In the above scenario, where your email service is separate from your hosting, email services will notice when everything doesn’t match up and flag these emails as SPAM.

    The way to identify this type of issue, refer to the screenshot below:

    Another situation clients encounter is when your website domain is different from the domain you use for your emails. This is actually the case with Fountain City. Once upon a time, we used the primary domain of Then when new top-level domains became available, like .tech, we scooped up But we continue to use as our main email address.

    SMTP (Simple Mail Transfer Protocol) is a method that we can use as an external service to send emails and fix authentication issues. We refer to these services as a “mailer.” Setting up a mailer will also help in cases where emails are not sent properly because of server configuration issues. For instance, some servers do not use the native WordPress mailing function.

    There are two main categories with which these mailers fit. Each of these has its advantages and disadvantages, so choosing which option depends on your company’s needs and circumstances.

    1. Transactional email providers. SendInBlue, MailGun, and SendGrid are popular options. These are separate from your email provider and send emails on your behalf. They typically include many other valuable features such as open rates, delivery rates, and other critical statistics for your marketing department.
    2. Email account services. Google/Gmail, 356/Outlook, and Zoho Mail are some trusted ones. If you use Google Workspace for your business email, as we do, you can hook up your website to send your website emails through one of your authenticated email addresses.

    Note, there’s also sometimes the ability to send emails through an SMTP server instead of using a provider’s API. This method is often easy and convenient, but it is less secure than the other mailers. Please note that your email provider may not allow you to send a large number of emails.

    Transactional email providers

    These are third-party services specializing in ensuring that your emails get to their intended targets and that you have more visibility into the entire process. Thus, these services will inform you when an email address has been bounced, flagged, or opened and how many times.

    Some services, such as SendInBlue, are primarily email marketing services that also include transactional email SMTP services. For example, MailChimp is primarily known for its email marketing, but after buying out Mandrill, it can also help with sending transactional emails.

    SendInBlue is had been Fountain City’s preferred transactional email provider because it’s easy to set up, delivers email quickly, adds as many domains and senders as you want, and is free up to the first 300 emails a day. This amount covers the needs of many small eCommerce businesses.

    SendInBlue is no longer our preferred provider because they’ve recently updated their terms of service that requires a minimum amount of account activity per month to keep an account online, and unfortunately sending via API or SMTP does not fulfill that. They want you to at least login every couple of weeks. Additionally, you need to be manually approved for the free tier of service, so it can sometimes take a couple of email exchanges.

    One frequent consequence of using a transactional email provider is that your emails will end up in a filtered “Promotions” inbox for some customers. Starting in 2013, this became especially true for users of Gmail. Google automatically moves marketing and bulk emails into the “Promotions” tab, including deals, offers, and other promotional messages. Emails sent through a transactional email provider like SendInBlue end up here because they are an Email Service Provider (ESP), like Constant Contact, MailChimp, Aweber, etc.

    Transactional emails may end up in promotions inbox.

    Inspect the email headers to indicate why this is occurring:

    Landing in the primary inbox is preferable because there are much higher open rates than those in Promotions.

    There are numerous articles that tackle this issue that you can review here:

    Keep in mind there is one thing that none of these articles suggest, which is not to use their services, and instead, choose SMTP through your primary email provider.

    Email account services

    Email account services seem like the obvious choice for most people because this is a service you already own and pay for, and the cost is generally free. In the case of Gmail, you can set this up to work with pre-existing Gmail addresses, G-Suite email addresses, Google Workspace aliases, or Gmail aliases at a custom domain.

    There are some drawbacks to these mailers. For example, Gmail’s API has rate limitations and several additional restrictions that can lead to challenges during setup.

    Establishing the Google Cloud application to tie the Gmail API can be complicated and intimidating for a non-developer. Thus, the Gmail mailer works well for sites that send low numbers of emails.

    If you don’t mind following highly technical instructions, nor need deliverability reports or other frills that Transactional email providers have, using these services increases your likelihood of these website emails delivered to the primary inbox, as seen below.

    I switched our SMTP to use Google API, and now contact form notifications and confirmations are going to the primary folder.

    The “mailed-by” data will match the “signed-by” data for emails sent through the original email service.

    I’m sold! So how do I set SMTP up?

    If you’re using WordPress, you’re in luck, as there are a lot of free plugins that can help. One of our favorites is WP Mail SMTP, partly because it’s one of the simpler plugins. It has impressive documentation to walk the inexperienced through everything, and it is a snap to integrate with SendInBlue or Google.

    In addition, it has a pro version you can also purchase for $49 a year, which gives you access to additional mailers, such as 365/Outlook, Zoho Mail, or Amazon SES. The pro version also gives you an email log accessible through the WP dashboard, but this is something you can generally get with other free mail-logging-specific plugins like WP Mail Logging.

    The other most popular WordPress plugin is Post SMTP Mailer/Email Log, which can handle a few more mailers, and has a built-in mail logger. But be aware, this software is a little more complicated to use for non-techies.

    There are additional CMS plugins; for example, if you’re on Shopify, SendInBlue has a free plugin just for this purpose.

    What next?

    If setting up your website to send emails to SMTP hasn’t resolved the issue of emails not appearing in inboxes, it could be that the content of your emails is just “too spammy .” You need to be able to send an email from your website to an inbox that passes the spam filter.

    1. Go to the website, grab an email address
    2. Send this address an email
    3. Go back to and check your score.
    4. If mail-tester never receives your email, there’s a problem with your host’s sending method. Contact your host, email provider, or ESP to let them know.

    Still no dice? Maybe you need some extra help? Give us a ring. We love solving challenging technical problems.