This post was updated and republished from 8/18/2010.
At SendGrid we are very serious about email deliverability. We live and breathe it each day. Similar to how Google keeps adjusting its search algorithm to provide the best results, we must also regularly adjust to ensure your non-spam email gets delivered. In this post we offer advice to help you make sure that your emails get delivered. Of course, the very best advice we can offer is to use SendGrid.
Photo Credit – nobody loves spam, except possibly this person
For additional information, check out our Tips & Tricks to Stay Out of the Spam Folder Guide.
If you are sending “any electronic mail message, the primary purpose of which is the commercial advertisement or promotion of a commercial product or service,” then you must comply with the following 7 main requirements (or face penalties up to $16,000) :
If your email contains only transactional emails or relationship content, then you are exempt from these rules; however, you must still not include false or misleading routing information.
Unfortunately, there is no complete list of spam trigger words. Further, it is not always the case that your email will end up in the spam filter simply by using a so-called trigger word.
The key thing to remember, is that a spam filter is trying to remove commercial advertisements and promotions. So generally, words that are common in such emails should be avoided or used sparingly. That said, take a look at these 100 Spam Trigger Words & Phrases to Avoid.
Phishing emails are designed to steal your identity by getting you to click on a fraudulent link. The most common method is for the email to be disguised as a legitimate email from a service you trust, such as your bank or a website you frequent. Thus, you want to avoid using phrases that are common to phishing attacks. At 24HourSupport.com you will find a short list of common phishing phrases along with references for further investigation.
This is a common, and easily preventable, cause for landing in the spam folder. Not only is this a good practice for avoiding a spam filter, but it also covers you in the case where the recipient can not view HTML emails.
Seth Godin coined the phrase “Permission Marketing,” and offers his thoughts here. There you will find sound advice on the ideas behind getting your customers or potential customers to give you the permission to email. Take it a step further at the point of subscription and ask to be placed on their white list.
Before sending emails out to your entire list, its worth the time to utilize a spam checking service.
MailingCheck.com offers a free downloadable tool for Windows that uses SpamAssassin to check. If you prefer to avoid downloading any software, you can send email to the IsNotSpam.com service and they will also check a few other items important to email deliverability. Alternatively, ProgrammersHeaven.com uses a form-based solution to test your emails.
If your email server is on a blacklist, it becomes extremely difficult to reliably send email, especially to new people on your lists.
The first step is to check if your email server is on a blacklist, following are a few free services:
If you find that you are on a blacklist, you will need to follow up with the website that has added you to their blacklist. That information is provided by the tools listed above.
It is usually best to not include images at all; however, if you must include images, here are some tips:
Spam Traps are email addresses that are flagged by ISPs as being no longer used by a human, so it then stands to reason that there could have been no opt-in. To avoid including a Spam Trap email in your mailing list, use a opt-in process and do not buy lists from email brokers.
In general, .jpg, .gif, .png and .pdf attachments are safe to send, provided you include some content in the email as well. However, executable attachments such as .exe, .zip, .swf, etc. should be avoided entirely. Generally, you should not send attachments to people on your list that are not expecting them.
If you need to email a large attachment or an attachment type that usually can be flagged as spam or trigger virus scanners, we recommend a service such as DropBox.com. If the attachment contains sensitive data, you may consider using your company’s secure FTP server.
You will want to make sure your email server supports these protocols (DKIM, SPF, Sender-ID and Domain Keys) and that they are properly implemented.
This alphabet soup helps ISPs determine the authenticity of your email from a technical perspective. To make sure yours are setup properly try using IsNotSpam.com‘s checking service.
If you want to dig deeper, here are the definitions:
If this whole process seems daunting and you would rather just focus on your company, we understand! Providing the best email deliverability is the reason we exist. You can either use our SMTP service to get started in minutes or you can utilize our REST API for maximum customization. If you’re just not sure, try us out for free.
This post was updated and republished from 8/18/2010.
Elmer Thomas is a Developer Evangelist at SendGrid. He works with developers at hackdays and conferences to further simplify the process of integrating with SendGrid’s APIs and to discover what new email challenges need to be conquered. When not on the road, he works on making life for developers using SendGrid frictionless.Elmer Thomas on Twitter • Elmer Thomas on Google+