Post SMTP Mailer (Postman) Review

If you own/manage a WordPress website(s), You might’ve noticed that it’s yet to introduce a more sophisticated email delivery system.

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  • Last Updated: 25 Mar 2023
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By default, WordPress utilizes php mail() for email delivery which is often troublesome due to various security and compatibility issues with hosting providers. So you may experience issues with email delivery if you choose to stick to the default configuration of WordPress. There might be various reasons for this, such as server configurations, security policies, and abuse prevention rules.

The easiest and most widely used solution for these email delivery issues is using a third-party SMTP service. SMTP stands for Simple Mail Transfer Protocol, and it offers a number of extra features such as the following that would come in handy when delivering emails.

  • Easy to connect (You just need SMTP credentials)
  • Higher security
  • Reliability
  • Automatically attempts to resend emails upon sending failures.
  • Scalability

Alright then, let’s use SMTP, but how to integrate it with WordPress? Again, very easy. You use an SMTP WordPress plugin from tons of plugins in the WordPress repository. 

In this article, let’s focus on one of the best and most popular plugins called Post SMTP Mailer/Email Log (Previously known as PostMan SMTP).

Plugin Features

  • Facilitates sending emails via SMTP server without depending on server capabilities and bypassing any restrictions of server/hosting provider.
  • Enables using free SMTP services such as Gmail, Yahoo, and Hotmail SMTP servers, provided you have an eligible account with them and credentials
  • Seamlessly connect your WordPress blog, Portfolio, Woocommerce store, or company website with your preferred mail server to handle all outgoing emails. Recipients of your emails would see them as if they are directly coming from your preferred email address.
  • Securely deliver emails to recipients with support for SMTPS, STARTTLS(SSL/TLS) encryption with SMTP authentication.
  • Option to specify a custom reply-to address, additional Cc and Bcc values, and additional headers.
  • Supports OAuth 2.0, providing the ability to not store credentials in the WordPress database for added security.
    The automated connectivity test and the setup wizard enables convenient setup. It’ll automatically scan your SMTP server to detect firewall blocks and eliminate configuration issues.
  • Provides the ability to Log and resend all emails and pinpoint the exact cause of an issue.
    Provides the ability to Log and resend all emails, and pinpoint the exact cause of the issue.
    Provides the ability to use an API if you can’t or don’t want to use SMTP. For instance, it supports Gmail/G Suite, Mandrill API, Mailgun API and Sendgrid API.
  • Compatible with almost every contact form plugin, number of newsletter plugins, and many more.
  • Support for extensions. The plugin supports the use of extensions to add new features without any changes to the plugin. There are few extensions available on the official website. (

Post-SMTP Mailer (PostMan) Pro Features

Post-SMTP Mailer (PostMan) does not offer a Pro version.

Installing and setting up the Post SMTP Mailer plugin

The installation process is similar to any other plugin. To begin, go to Plugins->Add New in the admin dashboard and search for “post SMTP.” Choose the “Post SMTP Mailer” plugin from the search results and click “Install Now.”

Once installed, activate the plugin. It will create a new menu entry called “Post SMTP” on your admin sidebar upon activation.

Configuration with Wizard

After the activation, you can see the warning provided by the plugin on its configuration. Click on “run the Setup Wizard.”

In this article, we will demonstrate how to set up Easy WP SMTP plugin to be used with the free nanoPost SMTP service. However, the same principles apply to any other SMTP service.

Wizard Step 1

You’ll be presented with an option to add the sender email address and sender name for your website. Note that this address will be shown as the Email Sender for your recipients.

Wizard Step 2

In this step, you can enter the hostname of your SMTP server. 

The plugin will automatically resolve the hostname as Nano Post’s SMTP server after a connectivity test.

Wizard Step 3

The wizard will automatically detect and select SMTP-STARTTLS with Password (Plain) authentication to host on port 587. Simply click next.

Wizard Step 4

In the next step, You can provide your credentials for the SMTP service. Simply insert them and click next.

Wizard Step 5

This step is optional. It sends you a notification whenever an email(s) fails to get delivered. You can choose to receive the notification via Email, Pushover, or via Slack. Optionally it’ll let you receive the notifications via a Browser addon ( via Chrome extension if you’re using Chrome. You’ll need to install the extension and add the UID you see in the extension).

Wizard Step 6

Click Finish to save and close the wizard.

You’d see that Postman is Configured in green if everything went smoothly.

Configuration with Manual config

*Alternatively, You can use the “manually configure” option if you’re an advanced user and/or would like to set every option manually.

In the manual option, you’ll be presented with five tabs to make necessary configurations.

Manual Config: Tab – Account

In this tab, you need to fill in the necessary information on the SMTP service.

Manual Config: Tab – Fallback

This tab allows you to define a fallback/alternative SMTP service in case of an email delivery failure in your primary SMTP service. You just need to add server details and credentials of your secondary SMTP service provider if you have one. 

This option is not mandatory and is used only when critical email delivery is required. 

Manual Config: Tab – Message

Here, you can configure which email address should act as your sender email and a name for the Sender.

It also lets you configure additional headers such as Cc and Bcc email address(s) and a custom reply-to address in case you need to get feedback/replies to different email addresses. Moreover, it allows you to add additional “To email” addresses for reasons such as record keeping.

You can also specify any custom headers as one per line if required. (e.g., X-MC-Tags: WordPress-site-A). However, use these custom headers with caution as they can negatively affect your Spam score.

Manual Config: Tab – Logging

The Post SMTP Mailer plugin has an email delivery log/audit log. It’s enabled by default, and you can disable it if you need. In this tab, you can configure maximum log entries and maximum transcript sizes for the log.

Manual Config: Tab – Advanced

This tab provides some advanced configuration options. Only change these values if you know what you’re doing.

Network Settings – Here, you can change the host server timeout values. Only change these values if your server keeps timing out on email sending/delivery. This also affects how long the user must wait for the mail server if it is unreachable.

PHP Log Level –  This Lets you choose which information should be included in the WordPress debug log. You can choose from Error, Trace, Debug, Warning, or Info unless you don’t want to add to the log.

Delivery Mode – This setting defines what should happen when emails are delivered. It’s often used in the stages of developing or testing. You can choose between “Log Email and Send,” “Log Email and Delete,” and “Delete all Emails” options. The “Log Email and Send” option is selected by default.

Stealth Mode – This lets you choose whether to keep or remove the Postman X-Header signature from messages.

Temporary Directory – This lets you define a path for a temporary directory for plugin operations. The directory should have Write permissions for the plugin.

Manual Config: Tab – Notifications

Here you can configure how you will be getting notifications. The notifications are related to email delivery and handled by the plugin. You can choose from the three options below, 

  • Get notifications to your WordPress admin email.
  • Get notifications via Pushover (You’ll need Pushover credentials)
  • Get notifications via Slack (You’ll need a Slack Webhook URL)

You also get the option to use and integrate a web browser extension (Only for Google Chrome and/or Chrome-based browsers). You need to install the extension and add the extension UID there to use this feature.

Once all done, click Save changes to activate your configurations.

Reasons To Choose Post SMTP Mailer Over Other Plugins

  • Supports SMTPS along with STARTTLS
  • Freely available
  • Provides the option to use custom Reply-to address, custom Cc and Bcc values along with the ability to use any custom header.
  • Supports OAuth 2.0
  • Provide an amazing built-in Email log.
  • Ability to try and re-send any failed emails.
  • Provide the use of an API along with SMTP.
  • Compatible with a vast number of contact form plugins, newsletter plugins, and core WordPress/Woocommerce features.
  • Feature a powerful configuration wizard integrated with an automated test tool that scans your SMTP server to avoid misconfigurations and suggest the best configurations.

Choosing An SMTP Service Provider

Selecting the best SMTP service provider that matches your requirements would not be an easy task. 

You can always choose a free SMTP service provider such as Gmail. However, setting up such an SMTP service would be painfully complicated, not to mention its limitations and complicated debugging processes.

A good SMTP service should be easy to set up for anyone, with a straightforward process on both server-side and client-side ( WordPress SMTP plugin in this case). Moreover, it should be reliable, secure, and compatible with all major email clients while offering satisfactory customer service.

nanoPost meets all these requirements and much more.

It offers a super easy and straightforward setup process. Quick registration and email verification are all that is needed for setting it up on the server-side. The whole process of configuring nanoPost as an SMTP service provider is limited to a handful of details for the client-side.