Block Disposable Email Addresses: Ensure Email Authenticity

Understanding Disposable Email Addresses

Before we can talk about how to block disposable email addresses, we need to understand exactly what they are.

What Are Disposable Email Addresses?

A disposable email address is a temporary address that expires after a short period. Also called a DEA, throwaway email, temporary email address, or anonymous email address, they allow users to sign up for email services and receive mail in a temporary inbox without having to provide their real or primary email address.

Types of Disposable Email Addresses

There are many disposable email services out there that allow a user to create a free email account and register for an email that will expire after an hour, a day, a week, etc. The user can opt to set up forwarding to their primary email address, view the emails they receive via the temporary service, or simply ignore any emails that are delivered to the temporary inbox.

Another form of temporary or disposable email address is “sub-addressing.” Sub-addressing means appending a tag to the username portion of the email so that emails can be filtered within a user’s primary inbox.

For example, a user might create the email address john+newsletters@gmail.com to use when signing up for mailing lists so that any incoming mailing list emails all end up in the same folder in their primary inbox.

Why Users Opt for Disposable Email Addresses

The main reason users choose to use temporary email addresses is to keep spam and unwanted emails out of their primary inbox. When a user signs up for an online service, they may be nervous that the service could be compromised (hacked or attacked) and their email address could be leaked to spammers.

Some users simply use disposable email addresses so they can sign up for mailing lists to get the free item offered on signup without actually having to receive emails from the mailing list.

Here are some of the better-known disposable email service providers:

• 10minutemail
• tempmail
• guerrillamail
• yopmail
• throwawaymail

The Impact on Email Marketing

Temporary email addresses have a substantially negative impact on email campaigns. Let’s examine why.

Consequences of Ignoring Disposable Email Addresses

If users use disposable email addresses to sign up for your mailing list, you will end up with those addresses on your list even after they expire. This will drive down your click and open rates, not to mention the fact that you’ll be paying to keep those expired email addresses on your list.

How Disposable Emails Affect Sender Reputation

Disposable addresses don’t just take up valuable space on your list: they can also hurt your sender reputation. When you send an email campaign, the number of failed deliveries, bounces, etc. is recorded by email service providers. Sending an email to a disposable email address that has already expired results in a bounce, which will count against your sender reputation.

Strategies to Identify and Block Disposable Emails

Now that we understand what disposable email addresses are and why they are harmful to your mailing list, let’s look at some strategies to identify and block them.

Real-Time Email Verification Tools

The best way to prevent disposable addresses from ending up on your list is to identify them in real-time, at the moment users attempt to sign up via your site’s registration form. The best way to do this is to use an email validation API such as AbstractAPI Free Email Verification API.

An email verification API accepts a network request containing an email for verification. The API runs several checks against the provided email, including typo checks, MX records, SMTP values, domain validity, and more.

A good email verification API will also check the address against a blocklist or blacklist of known disposable email domains and free email services to check free, disposable, catch-all, and role-based emails.

Here are a few of the top real-time email verification tools that you can use to catch invalid emails:

• AbstractAPI Free Email Verification API
• Zerobounce
• Pabbly
• GetEmail.io
• DeBounce
• Neverbounce
• Mailfloss

Preventing Disposable Email Registrations

The best way to prevent disposable email registrations is to create a brand with a mailing list that users want to subscribe to.

Building Trust with Subscribers

Building a trusted brand is about more than having a good website and a strong online presence. Your mailing list should provide high value to subscribers. Depending on your niche or sphere, you could offer discounts, industry tips, or high-quality content.

As well as providing high value to your subscribers, you should also treat your users’ data with respect and care. An email is a valuable and sensitive piece of identifying information. Never spam your users or sell their data, and make sure you are utilizing all security and privacy measures to make sure their data is secure.

How to Block Disposable Email Addresses

We’re going to take a quick look at how you can use a real-time email validation API to catch addresses from disposable email providers during sign-up. We’ll also talk about strategies for long-term mailing list maintenance.

Implementing Email Verification at Sign-Up

For this quick step-by-step tutorial, we’ll use AbstractAPI’s Free Email Verification API to catch invalid email addresses during user signup in a Javascript web app.

1. Get Started With the API

Navigate to the API home page and click "Start for Free." Sign up with an email address and password or login. Copy the API key you see in your dashboard.

2. Send an Email Validation Request to the API

Inside your Javascript code, create a function called sendEmailValidationRequest.

The function should accept an email address as its argument. Send an AJAX request to the API  with the email for validation included as an option in the query string.

The response from the API will look something like this:

{
  "email": "eric@abstractapi.com",
  "autocorrect": "",
  "deliverability": "DELIVERABLE",
  "quality_score": "0.80",
  "is_valid_format": {
    "value": true,
    "text": "TRUE"
  },
  "is_free_email": {
    "value": false,
    "text": "FALSE"
  },
  "is_disposable_email": {
    "value": false,
    "text": "FALSE"
  },
  "is_role_email": {
    "value": false,
    "text": "FALSE"
  },
  "is_catchall_email": {
    "value": true,
    "text": "TRUE"
  },
  "is_mx_found": {
    "value": true,
    "text": "TRUE"
  },
  "is_smtp_valid": {
    "value": true,
    "text": "TRUE"
  }
}

As you can see, the API checks the email for catchall, MX and SMTP records, valid formatting, role-based emails, free emails, and the thing we’re looking for: disposable emails.

Let's take a look at how we might use this in our code:

const API_KEY = "YOUR API KEY";
const API_URL = 
    "https://emailvalidation.abstractapi.com/v1/?api_key=" + API_KEY;

const sendValidationRequest = async (emailAddress) => {
    const fullURL = API_URL + "&email=" + emailAddress;
    const apiResponse = await fetch(fullUrl);
    const data = await apiResponse.json();
    const isDisposable = data.is_disposable_email.value;

    const isValid = isDisposable ? false : true;
    return isValid;
}

Regular Email List Cleaning and Maintenance

As well as catching disposable emails during signup, you should also be doing regular cleaning of your email list to purge any invalid addresses that may have slipped through the cracks. We recommend doing this at least once every six months.

Many online services do bulk email validation by allowing you to upload a CSV file of your email list and return a valid/not valid response for every email on the list. Check the services listed above for their bulk email pricing.

You can also use your email marketing provider to do list cleaning. Use the filters provided to isolate inactive emails (users who haven’t opened an email from you in the last six months, or who have only opened 1 or 2 of your emails, for example) and unsubscribe them from your list.

Conclusion

Disposable emails are a pain when they end up on your list, but it is relatively easy to deal with them as long as you have the proper tools in place. Check out our in-depth guides for more help implementing email validation in a modern React app, understanding the impact of sender reputation, or for a comprehensive comparison of ZeroBounce and NeverBounce.

FAQs

What is the difference between a disposable email and a regular email?

A disposable email is an email that is designed to self-destruct or expire after a short time (typically only a few hours.) They are anonymous email addresses that users can use to sign up for mailing lists and online services without having to provide a primary email address.

Can disposable emails be used for good?

A disposable email can provide a user with protection when signing up for online services that might be compromised or result in spam.

How often should I clean my email list?

It’s recommended that you clean an email list at least once every 6 months or more.