New email message previews for CloudMailin outbound sent email

We are excited to announce that CloudMailin now allows you to preview sent email messages whether they were sent via SMTP or our Email API.

For quite some time CloudMailin has allowed you to see a portion of the raw email, its plain text part and its HTML part. This has always been useful to see exactly what was sent but it never allowed you to fully explore the email content.

Now when you look in the CloudMailin dashboard you will see a number of tabs, these will let you see a preview of the email, the raw email, plain or HTML.

Checking sent emails for SPAM

Every email that's sent via CloudMailin is also checked for SPAM before it gets queued for delivery. This helps us to ensure that none of our customers are disrupting the email reputation of our other customers and helps to keep our outbound email delivery rates and reputation high.

We've also added the ability to inspect the SPAM score of your sent emails. This feature will probably only ever be available to customers on a case-by-case basis. However, it can be helpful to understand the score of your emails and to see how they are likely to be viewed by external mailboxes.

Using Test Mode to Preview Emails

All of the features mentioned above are also available when your emails are in test mode. This means that you can use CloudMailin to debug your emails before they're sent to your customers or during development of the email aspect of your application.

In order to use CloudMailin in your development environment just configure it as an SMTP server to use the API and then there are two options. You can either leave the entire account in test mode for development or you can set specific messages to work in test mode.

This way you have a development SMTP server that you can use to send emails that don't actually get queued for delivery. You can then use the CloudMailin dashboard to preview the emails and check their SPAM score.

How do email previews work?

When we first launched CloudMailin outbound we didn't have all of the tools available in modern browsers. One of the major challenges we wanted to overcome was not loading remote images or other resources from the internet.

Loading this content may affect and tracking or analytics customers have in place for their emails. There's also a potential security risk if a customer were to construct a malicious email. Thankfully modern browsers have actually made this much safer and simpler to acheive. CloudMailin uses a Content Security Policy (CSP) to ensure that no remote resources are loaded inside the iframe that displays the email. Although inline-styles are allowed, scripts or remote images should be blocked. This does however, assume you're using a modern browser.

Giving it a try

We've decided to launch this feature gradually in order to test things out. If you'd like to try it out please get in touch and we'll enable it for your account.