Struggling with WordPress emails landing in spam or not reaching users at all?
Password resets, order notifications, and customer updates are essential, but the default WordPress email system is not built for reliable delivery.
This can harm your brand reputation, frustrate customers, and reduce sales.
The solution is WordPress SMTP. Using a reliable SMTP plugin ensures your emails reach inboxes every time.
In this guide, we will show the best SMTP service providers, top WordPress SMTP plugins, and a step-by-step setup to improve your email deliverability.
What is SMTP?
SMTP (Simple Mail Transfer Protocol) is the standard protocol for sending and receiving emails online.
This mail delivery protocol bridges email clients and servers, ensuring that emails are transferred from the sender to the recipient.
When you send an email through an email client, such as Gmail or Outlook, SMTP is responsible for delivering the email from your client to the recipient's email server.
Table of Contents
- 1 How Does The SMTP Service Work When Sending Emails?
- 2 Why Use WordPress SMTP Instead of the Default PHP mail() Function?
- 3 6 Top SMTP Service Providers for WordPress
- 4 Top 5 WordPress SMTP Plugins for Reliable Email Delivery
- 5 How to Configure WordPress SMTP Settings Using a Plugin
- 6 5 Best Practices for Using WordPress SMTP For Email Deliverability
- 7 Commonly Asked Questions About WordPress SMTP
- 8 Does WordPress have SMTP?
- 9 What Are The Benefits of Using a WordPress SMTP Plugin?
- 10 Is WP SMTP free?
- 11 Can I use any email provider with SMTP?
- 12 What is the difference between SMTP and PHP mail?
- 13 How can I troubleshoot SMTP issues in WordPress?
- 14 What are SPF, DKIM, and DMARC, and why are they important for SMTP?
- 15 Start Using WordPress SMTP and Ensure Email Deliverability Today!
How Does The SMTP Service Work When Sending Emails?
SMTP is a crucial protocol that facilitates the reliable transfer of emails across the internet. It is the backbone of email communication, ensuring messages are delivered efficiently and accurately.
Note: SMTP handles sending emails. To retrieve emails from the server so recipients can read them, other protocols such as IMAP (Internet Message Access Protocol) and POP3 (Post Office Protocol) are used.
Let’s break down how this works step-by-step:
Step 1: Connection establishment
When WordPress or your email client sends an email, it first establishes a TCP connection to the SMTP server. The client identifies itself to the server with a HELO or EHLO command to start communication.
This connection is initiated using the Transmission Control Protocol (TCP), where the client sends a HELO or EHLO command to the server. This command identifies the client and starts the communication with the server.
Step 2: Data packaging and transfer
Once the connection is established, the email client packages the email data. This includes:
- Sender’s address: Identifies who is sending the email.
- Recipient’s address: Specifies who the email is intended for.
- Subject line: Gives a brief overview of the email’s topic.
- Message body: Contains the main content of the email.
- Attachments: These include any files or images being sent.
The client sends this data to the SMTP server for processing.
Step 3: Domain verification and routing
After receiving the email, the SMTP server utilizes a Mail Transfer Agent (MTA) to verify the recipient’s domain.
Suppose the recipient’s email address is hosted on a different domain. In that case, the server queries the Domain Name System (DNS) to locate the appropriate Mail Exchange (MX) record, which provides the recipient server’s IP address.
This record provides the IP address of the recipient’s mail server.
Step 4: Email relaying across servers
If the initial SMTP server isn’t the final destination, it relays the message to another mail server.
This involves repeating the SMTP process as the email travels through multiple servers until it reaches the recipient’s mail server.
Each server ensures that the email is routed accurately using the DNS-based information.
Step 5: Connection termination
Once the email has been successfully delivered to the recipient’s mail server, the SMTP server sends a confirmation back to the client.
At this point, the client issues a QUIT command, terminating the connection. This frees up resources and properly closes the session.
What is a WordPress SMTP Plugin?
A WordPress SMTP plugin enables WordPress websites to send emails via SMTP rather than the default PHP mail function.
As mentioned earlier, WordPress’s built-in email functionality is unreliable for high-volume or critical emails because it relies on the web host’s servers to send them, which can lead to deliverability issues, such as emails going to spam or not being sent at all.
An SMTP plugin solves this problem by allowing you to configure your website to use a dedicated SMTP server for sending emails.
Why Use WordPress SMTP Instead of the Default PHP mail() Function?
For many reasons, you should pick an SMTP service provider instead of the default PHP mail(). Here are the important reasons:
1. Email deliverability
The main reason why you should pick an SMTP service is email deliverability. If you use the PHP mail() function, your emails will often be marked as spam or not delivered due to a lack of proper authentication.
On the other hand, SMTP uses proper authentication methods, such as username and password, which makes your emails more trustworthy and results in them landing in the inbox.
2. Authentication and security
The PHP mail() function doesn’t provide robust email authentication mechanisms like DKIM (DomainKeys Identified Mail) or SPF (Sender Policy Framework), which are critical for verifying the sender’s identity.
Contrary to PHP mail(), SMTP allows you to configure secure authentication methods like SSL/TLS encryption and use your domain’s email credentials. This makes your emails more secure and verifiable, marking them as safe.
3. Tracking and monitoring
You don’t get any tracking or reporting features with PHP mail(). There is no way to know if your emails are being delivered or opened.
However, SMTP mail service providers allow for integration with email tracking and reporting tools. You get a detailed email log and can easily track how your emails are being delivered or rejected.
4. Avoiding server overload
You can’t send a large volume of emails using PHP mail() as it can burden your web hosting server. This will lead to slower site performance and potential server crashes.
SMTP offloads the email-sending process to external servers (such as an SMTP provider), reducing the load on your web hosting server and ensuring smoother site performance, even when sending large emails.
5. Email reputation
Since PHP mail() uses your web server’s IP address and shared hosting environments often have poor email reputations, this can result in your emails being blocked or filtered as spam.
With SMTP, you can use trusted email services with a strong email reputation (e.g., SendGrid, Mailgun, etc.), improving your sender reputation and reducing the chances of being blacklisted.
Now that you know its SMTP service provider is better than PHP mail(), move to the next section to learn more about the benefits.
6 Top SMTP Service Providers for WordPress
A WordPress SMTP plugin depends on a reliable service provider to ensure your emails are delivered successfully. Here are some of the most popular options:
1. SendLayer
An easy-to-use and lightweight SMTP service designed to improve email deliverability for WordPress sites. It ensures instant delivery for transactional emails and seamlessly integrates with WordPress and WooCommerce.
2. SMTP.com
SMTP.com is an affordable service provider that ensures 99.99% uptime and high deliverability. It is very easy to set up and use with WordPress sites.
3. Brevo (formerly Sendinblue)
An all-in-one email platform offering both SMTP and marketing services. It guarantees a 99% email delivery rate and integrates with all popular CMS platforms, including WordPress.
4. Amazon SES
Amazon SES is a cloud-based email service that ensures reliable deliverability. Whether you send transactional emails, marketing emails, or newsletters, you can depend on this SMTP service provider.
5. Postmark
Postmark focuses on transactional emails, offering fast delivery and high reliability. You can integrate it with your WordPress site to ensure emails reach users’ inboxes successfully.
6. Elastic Email
Elastic Email is a reliable service provider offering both transactional and marketing email capabilities. You can trust it to send your WordPress emails efficiently.
Note: Experts do not recommend Google (Gmail API) or Outlook due to limitations, such as Google’s 2,000 emails/day (500 for trial accounts) and their focus on one-to-one communication.
Top 5 WordPress SMTP Plugins for Reliable Email Delivery
Here are the top WordPress SMTP plugins our expert put together to give you the best options available:
1. WP Mail SMTP
WP Mail SMTP works by reconfiguring WordPress to use a proper SMTP provider when sending emails to ensure 100% deliverability.
It also has an email logging feature that records all sent emails in WordPress. Email logging helps you archive, audit, resend, or test email delivery and formatting.
Key Features:
- Supports: Amazon SES, SendGrid, Mailgun, Postmark, SendLayer, SMTP.com, Brevo, Elastic Email, and many more.
- Easy-to-use setup wizard for seamless configuration.
- Email logging to monitor sent messages and troubleshoot issues.
- Supports backup connections, email alerts, smart conditional routing, etc.
Price: A free version is available. The pro version starts at $49.00/ year.
2. Post SMTP
Post SMTP is a next-generation WordPress SMTP plugin that ensures email deliverability of all your WordPress emails. It helps you configure an email server with proper authentication that guarantees the delivery of your emails.
Key Features:
- Supports: Amazon SES, SendGrid, Mailgun, Postmark, Elastic Email, Brevo, Yahoo, Gmail and more.
- Easily view, filter, and check the status of all your WordPress emails.
- Instant email delivery failed notification.
Price: Free. The pro version starts at $49.99/yr
3. Easy WP SMTP
Easy WP SMTP is perfect for those seeking a hassle-free way to send emails from their WordPress site. This plugin allows you to send outgoing emails through eight transactional mailers or an SMTP server.
Key Features:
- Supports: SendLayer, Amazon SES, Mailgun, Microsoft 365 / Outlook, SendGrid, Brevo, SMTP.com, Postmark, etc.
- Option to log all sent emails, resend emails and store attachments.
- SSL/TLS support for secure email transmission.
- User-friendly interface and detailed error logging for troubleshooting.
Price: A free version is available. The pro version starts at $49.50 /year.
4. SMTP Mailer
SMTP Mailer offers a simple solution for WordPress users looking to improve their email-sending capabilities. This WordPress SMTP plugin takes control of the wp_mail function and utilizes SMTP for email delivery.
Key Features:
- Supports Bluehost, Brevo, Gmail, and other popular services.
- SSL/TLS support for enhanced email security.
- Intuitive interface for straightforward setup
Price: The plugin is free to use.
5. Mailgun for WordPress
Mailgun is a good option for those looking to use an SMTP server. It offers alternative methods (like HTTP API) to send emails without relying solely on SMTP.
It comes with advanced deliverability features to reduce bounce rates and spam complaints.
Key Features:
- Supports: Direct integration with Mailgun.
- Real-time email tracking and advanced analytics
- Provides detailed email logs
Price: A free version is available, and the premium version costs $15 /month.
All the plugins listed are suitable for integrating SMTP into your WordPress site to ensure proper email deliverability.
Move to the next section to learn how to integrate one of these WordPress SMTP plugins on your site.
How to Configure WordPress SMTP Settings Using a Plugin
This section will explain how to use WP Mail SMTP on your WordPress site. As this plugin supports all the popular and reliable SMTP service providers, the free version is good enough to start using it on your site.
Here is how you can integrate an SMTP service on your website by configuring the WordPress SMTP plugin.
Step 1: Install and activate the WP Mail SMTP plugin
We’ll use the free WP Mail SMTP version in this tutorial. To do this, go to Plugins ⇒ Add New Plugin, search for “WP Mail SMTP,” and then install and activate the plugin.
Step 2: Select the SMTP service
Next, go to WP SMTP Mail ⇒ Settings and hit the option “Launch Setup Wizard.”
Then, hit Let's Get Started.
Next, choose the SMTP service you want to use.
The WP SMTP Mail plugin recommends SendLayer, SMTP.com, and Brevo (Sendinblue) because they can send bulk emails without triggering spam filters. However, you can pick the one you like from the list.
Note: Continue using SendLayer specifically for sending transactional emails, like order confirmations, shipping updates, or password reset emails. For marketing and newsletter emails, however, you're free to connect and use a different email service that's designed for bulk email delivery.
Hit the ‘Save and Continue’ button when done.
Step 3: Configure the SMTP mailer settings
In the next step, copy and paste the API key of the SMTP service you selected above.
Now enter the From Name, From Email, and other information. Use the same business email address to set up your SMTP mailing service.
Experts also recommend checking ‘Force From Email’ to ensure your WooCommerce emails don’t go to spam.
Click on ‘Save and Continue’ once done.
Step 4: Enable the email features
Next, enable the email features you want. To fix the WooCommerce issue of not sending emails, you can enable improved email deliverability and email error tracking.
A few premium additional features are also available with a WP Mail SMTP Pro version.
You can skip the next two steps because it asks to enable intelligent recommendations and activate the plugin’s premium version.
Once done, hit the ‘Finish Setup’ button.
Well done! You’ve successfully set up the WP Mail SMTP plugin on your website.
Step 5: Send a test email to ensure deliverability
Navigate to WP Mail SMTP ⇒ Tools from the WordPress dashboard. On the ‘Email Test’ tab, send a test email.
Enter your email address, enable the HTML format, and click the ‘Send Email’ button.
If you’ve set up everything correctly, you should be able to see a “Success” message. Make sure to go to the inbox to see the email you received.
Note: Emails may fail if they don’t follow rules like marking as transactional or adding an unsubscribe link. FunnelKit Automations makes it easy to stay compliant and design beautiful emails.
5 Best Practices for Using WordPress SMTP For Email Deliverability
1. Select a trusted SMTP provider
Choose a reputable SMTP service like SendGrid, Mailgun, or Amazon SES. These providers are known for their high deliverability rates and provide features that help ensure your emails reach the inbox.
2. Implement email authentication
Set up authentication protocols such as SPF, DKIM, and DMARC. These protocols verify that your emails are legitimate and reduce the likelihood of them being flagged as spam.
3. Craft quality content
Ensure that your email content is well-written, relevant, and avoids spammy keywords. Use a professional layout and include HTML and plain-text versions to cater to various email clients.
Note: The stunning email shown above is built with FunnelKit Automations.
4. Maintain a clean email list
Clean your email list regularly by removing inactive or invalid addresses. Use double opt-in methods to confirm subscriber interest, which helps improve engagement and deliverability.
5. Monitor bounce rates and engagement metrics
Keep track of bounce rates, open rates, and click-through rates. High bounce rates can negatively affect your sender’s reputation, so address any issues identified through these metrics.
With FunnelKit Automations, you get detailed analytics of all your WordPress email campaigns, as shown in the above image.
Note: For more details, check our detailed guide on email deliverability best Practices.
Commonly Asked Questions About WordPress SMTP
Still got questions? Here are some of the frequently asked questions about WordPress SMTP with answers:
Does WordPress have SMTP?
No. WordPress does not have built-in SMTP functionality by default. It relies on the PHP mail function to send emails. However, you can add SMTP capabilities using any WordPress SMTP plugin.
What Are The Benefits of Using a WordPress SMTP Plugin?
Using a WordPress SMTP plugin has several key benefits for improving email deliverability and security:
- Improved Email Deliverability
SMTP ensures that your emails are properly authenticated, reducing the likelihood of them landing in spam folders and increasing the chances of them reaching your recipient's inbox. - Secure Email Transmission
SMTP plugins often support SSL or TLS encryption, ensuring that emails are securely transmitted over the internet, preventing unauthorized access or tampering. - Email Tracking and Logging
Many SMTP plugins provide detailed email logs, allowing you to track sent emails, monitor their status, and troubleshoot any delivery issues. - Reliable Transactional Emails
SMTP ensures that important emails, such as order confirmations, password resets, and customer notifications, are reliably delivered to users' inboxes, enhancing the user experience.
Is WP SMTP free?
Yes. Many WordPress SMTP plugins, such as WP Mail SMTP, offer free versions with basic features. Some premium features may require a paid subscription, but basic SMTP functionality is typically available at no cost.
Can I use any email provider with SMTP?
Yes, you can use any email provider that supports SMTP, including services like SendGrid, Mailgun, etc. Just ensure you have the correct SMTP settings for the provider you choose to configure in your WordPress site.
What is the difference between SMTP and PHP mail?
SMTP is a dedicated email protocol for better deliverability and security. In contrast, the PHP mail() function is less reliable and can result in emails being marked as spam more frequently.
How can I troubleshoot SMTP issues in WordPress?
If your WordPress site isn’t sending emails properly, start by checking your SMTP configuration. Make sure your SMTP host, port, encryption type (SSL/TLS), username, and password are entered correctly in your SMTP plugin. Even a small typo can prevent emails from being sent.
Next, confirm that:
- Your hosting provider is not blocking SMTP ports (commonly 25, 465, or 587).
- SMTP authentication is enabled.
- Your email provider supports external SMTP connections.
- Your domain has properly configured SPF, DKIM, and DMARC records to prevent deliverability issues.
You should also send a test email from your SMTP plugin and enable debug logging to view detailed error messages. These logs usually reveal whether the issue is related to authentication, DNS configuration, server connectivity, or rate limits.
If the problem continues, check your SMTP provider’s status page for outages or contact their support team.
What are SPF, DKIM, and DMARC, and why are they important for SMTP?
SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) are authentication protocols that help improve email deliverability and security. These protocols verify that your emails are sent from authorized servers and ensure they aren’t tampered with in transit.
- SPF: Helps verify that the email sender is authorized to send emails for a domain, reducing the risk of spoofing.
- DKIM: Ensures the email content hasn’t been altered during transit by adding a digital signature to the email.
- DMARC: Builds on SPF and DKIM by instructing email servers on how to handle emails that fail authentication, helping protect against phishing attacks.
Together, these protocols work with SMTP to ensure your emails are trusted by recipients' servers, significantly reducing the chances of being marked as spam.
Start Using WordPress SMTP and Ensure Email Deliverability Today!
Using WordPress SMTP is essential for effectively communicating with your customers. Sending emails is pointless if they don’t reach users’ inboxes or your target audience doesn’t read them.
The good news is that with the right WordPress SMTP plugin, you can easily integrate SMTP into your WordPress site in just a few simple steps.
You can choose any email service provider, but ensure it’s compatible with SMTP.
By following the process we’ve shared, configuring WordPress SMTP is straightforward.
So, set up SMTP on your WordPress site and ensure your emails reach your users' inboxes!
Also, to improve your email open rate with a personalized subject line and click rate with stunning emails, get FunnelKit Automation today.
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