Sending out emails is a day-to-day task for almost every individual, particularly for businesses that use them to communicate with potential clients and customers. However, thorough email testing is critical to look out for errors like typos, layout issues, formatting errors, and related flaws. The testing strategy, though, depends upon the quantity, complexity, and features of your email. While choosing a specific tool to facilitate email testing may be challenging, it is an ideal way to find out if the performance is affected by any means. In this guide, we will find out all about smtp4dev to help individual developers with simple email testing.

Smtp4dev: What is it?

Smtp4dev also referred to as the fake SMTP server, is an open-source application that mimics an SMTP email server to both test and debug emails. Although it acts as a regular SMTP server, it obstructs and saves outgoing emails instead of sending them. Hence, you can scan them via a web interface to check if they are correct before passing them on.

How does Smtp4dev function?

In its internal workings, all applications use the SMTP Protocol to send emails. The email, then, progresses from the client to the domain's SMTP server. The server then forwards the email to on to the recipient's client or passes it on to other servers till it finally reaches the receiver.

Basically, Smtp4dev watches for outgoing emails on port 25. The emails are then displayed in a web app. You just have to set up your application’s SMTP host to point to your machine with smtp4dev. Following this, you may manually examine all the sent emails on the web interface of smtp4dev.

First things first, you must run the smtp4dev. Ideally, Docker is the best tool to accomplish it. However, many people out there are not familiar with Docker. Simply put, it is a program that wraps software into containers and enables it to be utilized in various environments akin to virtualization.

When do we need Smtp4dev?

Smtp4dev comes in handy when various applications need to examine their email functionality whilst developing. To ensure your emails are relevant and correct, it is critical to constantly conduct tests against the production data. Doing so will help you to prevent annoying potential clients with subpar emails.

In case you are wondering, here is why using a real SMTP server is not preferable: Your email deliverability might suffer significantly and they might end up in the spam folder.

Emails sent via real SMTP servers do not guarantee immediate delivery. On the flip side, emails sent to smtp4dev are delivered instantly and are at a lower risk of being marked as spam. Thanks to its UI, you can analyze your email more efficiently. Hence, fake SMTP servers are the right way to go.

Restrictions of Smtp4dev

Although smtp4dev may be fantastic for email testing, its web interface is relatively restricted. For instance, emails that have HTML are shown as plaintext since smtp4dev does not parse HTML elements. In addition, there is just one view of the email; there are no ways to check how an email will be displayed by several email providers. Further, smtp4dev is unable to assist in examining and troubleshooting deliverability. For example, you will need additional tools to learn how spam filters perceive email.

Alternative Email testing tools

Among the best email testing solutions, configuring your application’s SMTP settings to save emails to a folder instead of passing them on to a server, is by far the most popular option. That said, the alternative testing options other than smtp4dev include:

  • Papercut: A local email testing tool.
  • MailCatcher: Has a similar functionality and interface as smtp4dev.
  • MailSlurp: A cloud-based email testing tool.
  • Other deliverability tools

Control your Testing Process with MailSlurp

Whether it’s test automation, SMTP server management, or deliverability, MailSlurp is with you through it all. Here’s the good news; our email testing documentation offers more than what smtp4dev and other tools do. Use MailSlurp and take pleasure in an easy testing life.