How to Detect Disposable Email Addresses: The Ultimate Guide

The Technical Side of Disposable Emails

Before we dive into how to scrub your mailing list of these temporary email addresses, let's take a quick look at how a disposable email address works, and how it is different from a regular and correct email address.

How Disposable Emails Work

There are three types of disposable email addresses: alias addresses, forwarding addresses, and non-forwarding addresses.

An alias address is simply another email address set up under the user's primary domain, and any emails sent to this alias are filtered into a separate folder from the user's primary inbox folder. Because they are managed by popular domains like Gmail, these still technically count as "real" addresses.

A forwarding address is a separate email address set up under a different domain, which forwards emails to the user's primary account. The user might then apply to filter to manage incoming messages from their forwarding address.

A non-forwarding address is what we'll be discussing in this article. It's a temporary email address, handled by a company specifically set up to provide disposable email addresses to users. The address does not forward emails to the recipient's inbox and usually disappears after a certain amount of time.

The Benefits and Drawbacks of Using Disposable Email Addresses

From a consumer standpoint, it's easy to see why a disposable email address is attractive: today's inboxes are full of spam and unread emails. If you are worried about spam, a disposable email address is a good safety net for avoiding it.

Another benefit for the consumer using a disposable email address is protecting personal information. If a company you signed up with gets hacked, you won't have to worry about bad actors getting their hands on your real email address.

Finally, if all you want to do is leave a comment on a blog post, or get the free eBook offered for signing up for a mailing list, using a disposable email address to do this makes sense.

On the other hand, using a disposable email address might lead to missing important emails, which will not be forwarded to your main mail server.

How to Detect Disposable Email Addresses

It's not always easy to detect disposable emails. There are dozens of existing disposable email domain names, and more are being added every day. Keeping track of the list of disposable domains is a near-impossible task.

The only real way to detect disposable emails is to monitor the inboxes of those addresses and perform periodic audits to assess their deliverability of them. But again, this is a time-consuming task.

‍

For this reason, most companies turn to online services to handle disposable email address detection for them. Services like NeverBounce, ZeroBounce, AbstractAPI, and others can help you detect temporary email addresses so they don't pollute your list.

Let's take a look at how you can use AbstractAPI's Free Email Verification API to perform disposable email address detection and ensure that your mailing list is made up of only valid email addresses.

Using the API to Detect an Incoming Temporary Email Address

AbstractAPI exposes a REST endpoint that you can use in your online forms to perform real-time email validation and prevent fake emails from ending up on your list in the first place. Simply make a call to the API when the user inputs their email address, and you'll get a response telling you whether the email is real, valid, and active.

Get Started With the API

To use the Abstract Free Email Validation API, you'll have to sign up for an account and get an API key. The account is free for life. The API key authenticates you with the API and allows you to make requests.

Go to the home page and click "Get Started"

After you sign up, you'll be taken to the API dashboard, where you'll see your API key.

Send a Test Email Validation Request to the API

Choose your preferred language in the testing sandbox. For example, Javascript. You'll see a block of code that you can copy and paste into your own app or web form.

function httpGetAsync(url, callback) {
    const xmlHttp = new XMLHttpRequest();
    xmlHttp.onreadystatechange = function() {
    if (xmlHttp.readyState === 4 && xmlHttp.status === 200)
         callback(xmlHttp.responseText);
    }
    xmlHttp.open("GET", url, true);
                  xmlHttp.send(null);
    }

    const url = "https://emailvalidation.abstractapi.com/v1/?api_key=YOUR_API_KEY&email=eric@abstractapi.com"

    httpGetAsync(url)

This sends a GET request to the API with a single email address for verification included as a query string parameter. Your API key is also included as a query string parameter.

You'll get the following response from the API:

{
  "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, AbstractAPI checks for a few things when it looks for invalid email addresses:

• deliverability
• formatting
• temporary email
• free email
• role-based emails
• catch all emails
• valid MX records
• valid SMTP

All of these fields are important in detecting invalid emails. For this article, you can just look at the is_free_email and is_disposable_email fields. These will tell you whether or not the email is for a fake inbox.

AbstractAPI maintains thorough records of known disposable emails and continuously updates its database when new ones are discovered.

Using the Bulk Uploader to Detect Multiple Temporary Email Addresses

As well as using the endpoint to detect temporary addresses in real-time, you can use the bulk uploader to upload a CSV file of email addresses to the email verification API and find all the temporary emails that are already on your list.

Related: How to verify multiple email addresses

Click the "Bulk Upload (CSV)" link on the API dashboard. The bulk uploader dialogue will open. Click "Upload CSV" to upload a list of email addresses.

The API will accept them and run an audit on the entire list, and then you'll get an email with a link to a spreadsheet containing information about each email.

You can then use this information to remove the temporary email address instances from your list.

The Challenges of Detecting Disposable Email Addresses

Unfortunately, even third-party email verification API options are not infallible. As previously mentioned, new temporary domains are springing up all the time. In addition, VPNs and proxy servers can impact the deliverability even of real addresses.

Savvy users might also set up their own fake emails by simply creating a valid email address through a reputable mail server like Gmail that they only use as a throwaway account and never actually check.

However, this doesn't mean that auditing for disposable emails is not important. Using services to detect temporary email addresses will allow you to remove the majority of those addresses from your list, and is absolutely worth your time.

Conclusion

Disposable email addresses and temporary emails are attractive for users hoping to avoid spam, who want to keep their sensitive information safe, and who don't want to use their real addresses to sign up for mailing lists.

Unfortunately, this creates a problem for businesses that use email marketing to connect with their customers. To ensure that your marketing emails are being delivered, and aren't just going to throwaway accounts, you should use a service to detect trash emails.

There are two lines of defense against disposable email addresses: you should verify every incoming email address in real-time when users sign up. This prevents invalid emails from ever making it onto your list. Additionally, you should run periodic audits of your list through a bulk verification system to detect and remove disposable email addresses.

FAQs

What is a disposable email address?

A disposable email address is a throwaway email address that has been set up through a temporary domain name. It does not forward emails to the end user and often expires after a certain amount of time.

Why do people use disposable email addresses?

Users who are worried about receiving a lot of spam, or who want to keep their sensitive information private, often use disposable email addresses to avoid giving out their real email. Other users use temporary addresses to sign up for mailing lists so they can receive free content.

What are the risks of using disposable email addresses?

For the user, the risk of using a disposable email address is that you may end up missing important emails, which won't be delivered to your actual inbox. For businesses, disposable email addresses can hurt deliverability and increase bounce rates, leading to damage to your sender reputation.

Can email validation services detect all disposable email addresses?

Unfortunately, it is nearly impossible to detect all disposable email addresses, because there are already so many domains for disposable emails out there, and new ones are being added all the time. In addition, proxy servers and VPNs make things even more complicated.

However, this doesn't mean that detecting disposable email addresses is a waste of time or not important. Email validation services can detect and block the majority of disposable email addresses, and using them will improve your deliverability score and decrease bounce rates.