Email Service Provider (ESP)

We have often talked about email service providers (ESPs) or email providers, especially in posts about deliverability, because their decisions greatly affect the results of email marketing campaigns.

In this post I’m going to share some curiosities and useful information about email providers.

We’ll walk you through it here at Mailrelay.

What are email providers or ESPs?

Email providers, also known as ESP (Email service provider), are companies that offer the technical resources and means necessary to create an email account and thus have the ability to send and receive emails.

When you need to create mass mailing campaigns, you have to be very careful in choosing the email service provider, since part of the success of the campaigns is related to the ESP.

There are many ESPs or email providers, some paid and some free. Among the free ones, the most popular are Gmail, Yahoo!, Outlook (Hotmail), GMX Mail and Zoho.

Differences between an email provider and an email client

As we mentioned earlier, the email provider is the company that gives you your email account, along with the means to send and receive emails.

On the other hand, an email client is the application or software that would allow you to use the features offered by email providers (ESP).

In other words, the email provider allows you to create the email account on their servers and the email client allows you to access and read emails, send new messages and, in short, manage your emails.

Some examples of email clients are:

• Mozilla Thunderbird
• Microsoft Outlook
• Apple Mail
• Android Mail

The email provider is the company that gives you an email account, and the means to send and receive emails.

These applications let you manage your email account easily, manage your emails, send new ones, etc.

Differences between email providers and mass emailings

In general, the main purpose of most ESPs is to let you send individual emails or emails to small groups of people, whether personal or professional. This means they come with this limitation, and many others, when sending to very large groups of people (especially in the case of free ESPs).

Some of the most common limitations are: not being able to send more than 150 emails a day, not being able to send the same email to more than 50 contacts at once, no statistics on the emails sent, a cap of 30 emails per hour, etc.

An email marketing company, or a mass emailing company like Mailrelay, is exactly the solution for creating and sending mass emails without the restrictions that email providers impose when you want to send to thousands of addresses at once.

An email marketing provider lets you send to as many contacts at once as its customers want, provides sending statistics, handles unsubscribes, allows the use of autoresponders, segments contacts, makes it easy to design attractive emails, etc.

Email providers and mass mailing

Most email providers are designed for sending personal or professional emails to a small number of contacts, so they limit mass email sending.

On the one hand, they don’t allow sending to a large number of contacts, and on the other, they don’t allow sending emails at a high rate (too frequently, for example more than 150 emails a day).

With these restrictions, if you need to send a mass mailing you’ll need a tool for sending mailings or newsletters.

► How do email providers detect spam?

As you can imagine, email providers (ESPs) use various strategies to try to detect and stop spam.

Some of these strategies are:

• Reviewing the content: if it looks like spam, it may be spam, and when in doubt, it will end up in that folder. Using lots of images can hurt you.
• Reviewing the links: which websites do the links in the email point to? Using shortened links can hurt you.
• Reviewing the attachments: most ESPs will use some antivirus to scan the files attached to the email. Using unnecessary attachments can hurt delivery.
• Emails similar to spam messages: when many users mark a type of email as spam, emails with similar content may automatically be sent to the spam folder instead of the inbox. You need to be careful because if many contacts mark your emails as spam, your emails will gradually always end up in that folder.
• Domain history: different ESPs may keep a history of the emails a given domain sends, and of how the recipients rated them.
• Artificial Intelligence and Deep Learning: for example, Gmail uses machine learning systems to detect unwanted and phishing emails.

You can expect these kinds of strategies from the best-known email providers or servers such as Gmail, Hotmail, Outlook and Yahoo!

Other email providers, such as your hosting and domain provider, may use tools like SpamAssassin, a well-known tool for assessing whether an email is spam based on its content.

► What do email providers recommend to companies that send mass mailings?

The most general recommendations are:

• Increase your sending volume gradually. Start with a low volume and increase it little by little.
• Make sure you have the right technical settings (SPF, DKIM, custom domain …)
• Use a sender address from your own domain with all the settings mentioned above
• Send only to contacts who signed up voluntarily
• Make it easy for contacts to unsubscribe, for example with a clearly visible unsubscribe link

As you can see, the recommendations are fairly easy to follow and many are quite logical.

As well as helping your emails get received properly, they’ll help you earn your subscribers’ trust.

Important: even if you follow these recommendations, false positives can happen. Consistency is always the key.

► What can an email provider do with suspicious mailings?

This is a common concern for all email providers, since it affects their users day after day.

So if the provider suspects your emails, the actions it can take are:

• Mark the emails as spam, so they end up in that folder. In that case the emails are delivered, and the recipient may move them out of spam if they check that folder and want to *.
• Block the emails completely. In that case they won’t even be delivered. If they block your sending domain, none of the emails you send will reach their destination.
• Limit the number of emails they accept from the sender. In that case you may see many emails get queued. That is, they stay on hold, neither rejected nor accepted. In this case they may be delivered little by little. The email provider uses this time to observe what users do with these emails.

* NOTE: The easiest way for this to happen is during the subscription process, since the subscriber has just taken the action and is more likely to go looking for the email.

Most widely used email providers

Although there are countless email providers, currently the most well-known and used would be the following:

• Gmail: Offers 15 GB of storage space and allows you to attach photos, videos and documents to emails.
• Outlook: Allows you to schedule emails and create new meetings and appointments. It also has an application for Android and iOS.
• Mail.com: Provides 2 GB of online storage.
• Yahoo! Mail: Allows you to add other email services and integrate a calendar.
• Zoho Mail: Ideal for businesses, it offers a set of applications and facilitates team collaboration.
• Inbox.com: Offers 1 TB of storage and protection against spam and viruses.
• GMX: Provides 65 GB of storage and allows you to send attachments of up to 50 MB.
• Fastmail: It is a premium service that offers privacy and control with 2 GB of storage in its basic plan.
• ProtonMail: Known for its security, it offers end-to-end encryption.
• AOL Mail: Offers unlimited storage and advanced protection against spam and malware.

These providers are characterized by offering different storage capacities, security options, and email management tools.

These tools may be relevant to users depending on their specific needs.

Related entries

• Headers
• CTA (Call To Action)
• Email marketing campaign
• Newsletter campaign
• Winback campaign
• Email Campaigns
• Drip campaigns
• Advertising campaigns