How to Verify and Validate Email Addresses Before You Send

Unsubscribers, spam complaints, staggering bounce rates.

Within the realm of email marketing, it is up to you how to approach these common obstacles: reactively or proactively. Although a reactive approach makes identifying email complications easier (because you’re waiting for them to happen), a proactive approach represents the things you can do now, before the complications arise, to ensure your email campaigns remain healthy.

Learning how to verify and validate email addresses before you send an email is one of the best ways to maximize the effectiveness of your email marketing efforts. Think of it as paving the road before you drive it rather than waiting for the potholes to introduce themselves to you.

Looking for more proven email marketing strategies? The OneSignal guide to email optimization covers everything from mobile design to send time and frequency adjustments.

What is the Difference Between Email Validation and Email Verification?

Though often used interchangeably, email validation and verification are two different processes with completely different levels of depth.

What is Email Validation?

Email validation is the process of checking whether an email address is properly formatted and follows standard syntax rules. The primary goal of email validation is to ensure that an email address is correctly structured and does not contain any obvious errors or typos. The validation process typically involves checking for the presence of "@" symbol, the domain name format, and the absence of spaces or special characters.

For example, during email validation, an address like "john.doe@example" would be flagged as invalid due to the missing ".com" or domain extension. Similarly, an address like "john doe@example.com" would be considered invalid due to the presence of a space.

Email validation helps to identify and eliminate invalid or poorly formatted email addresses before they are added to your mailing list or used in email campaigns. However, it does not guarantee the deliverability or existence of the email address.

What is Email Verification?

Email verification goes a step beyond email validation. This process not only confirms whether an email address is valid in terms of syntax but also involves checking the existence of the email domain and validating that the mailbox is able to accept incoming emails.

During email verification, various techniques like checking the DNS records (MX records) of the domain, performing a ping test, or using SMTP (Simple Mail Transfer Protocol) commands are used to verify the email address's deliverability. We will cover these processes later in this article.

Email verification helps to identify not only invalidly formatted addresses but also inactive or non-functional email addresses that might lead to bounces or affect the sender's reputation negatively. When you verify your email list you are promoting better email deliverability rates and improving the chances of reaching the intended recipients with your campaigns.

Why Email Verification and Validation Matter

While practicing some intentional “email marketing hygiene” doesn’t sound like fun work, it’s ultimately the task that sets up your campaigns for efficiency and for avoiding negative campaign metrics (unsubscribes, high email bounce rates, and low click-through rates.)

Verification and Validation Keep Your Email List Clean!

We can’t talk about email verification and validation without discussing the importance of keeping a clean email list. When you regularly verify and update your email list, you reduce the chances of sending emails to invalid or inactive addresses that result in bounces. High bounce rates can signal to email service providers that your emails are not valuable or engaging, leading to lower deliverability rates and potential placement in recipients' spam folders.

By keeping your list “clean,” you demonstrate to email providers that you are a reputable sender, increasing the likelihood of your emails reaching your audience's inbox.

Learn more about what causes email bounces!

It’s also worth noting a clean email list almost always improves engagement and conversion rates. Sending emails to a targeted and engaged audience increases the likelihood of recipients opening, reading, and acting upon your marketing messages. The less time and resources you spend on uninterested or non-responsive recipients, the more you have to focus your efforts on those genuinely interested in your content!

As a result, you can expect higher click-through rates, lower unsubscribe rates, and an overall higher brand perception among your subscribers.

How do you handle email unsubscribes when you can’t prevent them? Our guide on managing and avoiding email unsubscribes goes into everything you need to know.

How Invalid Email Addresses Affect Your Sender Reputation

If unchecked, invalid email addresses create a bit of a cascading avalanche of email performance issues, especially as it concerns your ESP (email service provider) reputation.  

When you send emails to a large number of invalid or non-existent addresses, it results in a high bounce rate, indicating to email service providers that your email list may be outdated, purchased, or poorly managed. A high bounce rate signals a lack of engagement and relevance, leading to email providers classifying your emails as potentially spammy or low-quality. Consequently, your sender reputation diminishes, and your future emails are more likely to end up in recipients' spam folders, affecting your overall deliverability and diminishing the effectiveness of your email marketing campaigns.

How to Validate an Email Address Without Sending an Email

Now that we understand the importance of email verification and validation, let's dive into some actionable strategies that will help you give your email list a serious tune-up.

Opt-in and Double Opt-In

Implementing an email opt-in strategy involves providing users with the option to subscribe to your email list voluntarily. This initial consent serves as the first step of validation, ensuring that the email address is not obtained through illegitimate means or without the owner's knowledge. To encourage sign-ups, place clear and visually appealing sign-up forms on your website, blog, or landing pages. Offer an incentive, such as a discount, exclusive content, or access to a valuable resource, to entice visitors to subscribe. Additionally, ensure that the opt-in process is user-friendly and hassle-free, with a prominent call-to-action (CTA) that clearly communicates the benefits of joining your email list.

A double opt-in takes the process one step further by requiring subscribers to confirm their intent to join the email list through a verification email. After users sign up, an automated email is sent to their provided address, asking them to click a confirmation link. This step further ensures that the email address is valid and that the subscriber genuinely wants to receive emails from you. While double opt-in may lead to a slightly smaller list size, it results in higher engagement and reduces the chances of fake or mistyped email addresses cluttering your list.

Here are some tips for implementing new subscriber confirmation emails:

• Automate the Process: Set up an automated confirmation email to be sent immediately after someone subscribes to your email list. This ensures a seamless and timely experience for the new subscriber.
• Personalize the Content: Make the confirmation email welcoming and personalized. Address the subscriber by name, express gratitude for joining, and reiterate the value they will receive from your emails. Learn more about email segmentation best practices here!
• Include Clear Call-to-Action (CTA): Clearly instruct the subscriber to click the confirmation link or button to complete the subscription process. Use a prominent CTA that stands out and encourages action. Start writing better CTAs and don’t forget to A/B test!
• Explain the Benefits: Remind subscribers of the benefits they will receive by confirming their subscription. Highlight exclusive content, promotions, or useful information they will gain access to.
• Set Expiration Time: Encourage prompt action by setting an expiration time for the confirmation link. This fosters a sense of urgency and helps keep your list free from inactive or uninterested subscribers.

By combining opt-in and double opt-in measures, you create a powerful mechanism for building and maintaining a legitimate email list from the get-go rather than leaving more verification work for yourself down the road.

Email Syntax and Formatting Checks

Email syntax and formatting checks are an essential part of the email validation process, as they help identify and correct errors in email addresses before they cause deliverability issues or affect the quality of your subscriber list

To ensure that email addresses follow the correct syntax, you can implement validation checks during the sign-up or data-collection process. Use regular expressions or validation libraries to verify that email addresses contain the "@" symbol, a domain name with at least one period (e.g., ".com," ".org"), and valid characters without spaces or special characters.

Regular expressions – A set of programming sequences that match and manipulate strings of text, allowing you to find and validate specific patterns within a larger text.

Validation libraries – Pre-built software components or frameworks that provide various functions to validate email addresses. Many programming languages have their own validation libraries or built-in functions for email validation.

Additionally, set up client-side validation on your website's sign-up forms to provide real-time feedback to users, prompting them to correct any formatting errors before submitting their email addresses.

Identifying common formatting errors involves checking email addresses for frequent mistakes made during data entry, such as missing "@" symbols, spaces, or incorrect domain names.

Common formatting errors worth correcting include:

• Missing "@" symbol or multiple "@" symbols
• Spaces before or after the email address
• Lack of a top-level domain (TLD) extension (e.g., ".com," ".org")
• Incorrect placement of dots or underscores
• Using invalid special characters
• Repeated or missing characters in the domain name (e.g., "yahooo.com" or "yaho.com")
• Using non-alphanumeric characters in the domain (e.g., "yah*oo.com")
• Entering the email address in all uppercase or lowercase
• Using a domain name that doesn't exist or is misspelled (e.g., "gmal.com" instead of "gmail.com")

Domain and MX Record Verification

Validating the domain of email addresses ensures that domains are legitimate and active, increasing the chances of successful email delivery. Additionally, checking the Mail Exchange (MX) records of the domain verifies the existence of a mail server capable of receiving emails.

Let's look at both these processes:

Validating the Domain

To validate the domain of an email address, you can follow these steps:

1. Domain Syntax Check: Ensure that the domain name follows the standard syntax rules. It should contain only alphanumeric characters, hyphens, and dots, with no spaces or special characters.
2. DNS Lookup: Perform a Domain Name System (DNS) lookup to check the domain's authoritative DNS records. A successful lookup confirms the existence of the domain and its configuration.
3. WHOIS Lookup: Utilize WHOIS lookup tools to obtain domain registration information. Verify that the domain is registered and has not expired or been suspended.
4. Domain Blacklists: Check if the domain is listed on any email blacklists, as this can indicate spammy behavior or suspicious activity.

Checking MX Records for Mail Server Existence

To verify the existence of a mail server for the domain, follow these steps:

1. MX Record Lookup: Perform an MX record lookup for the domain to identify the mail servers responsible for receiving emails. The absence of MX records indicates that the domain cannot receive emails.
2. SMTP Handshake: Establish an SMTP (Simple Mail Transfer Protocol) connection with the mail server and initiate a handshake. A successful handshake confirms the mail server's readiness to accept incoming emails.
3. Ping Test: Conduct a ping test on the identified mail servers to check their responsiveness. A successful ping indicates an active and reachable mail server.
   
   An email ping test is similar to a regular internet ping, but instead of checking if a website or server is responsive, it checks if an email address is valid and active. It's like sending a tiny signal to the email address, and if it receives the signal and responds, it means the email address is likely working and can receive emails.

Choosing an Email Verification Tool

There are numerous third-party email validation services, such as ZeroBounce, that email marketers can use. Many of these services can verify the syntax of email addresses, check for common formatting errors, and assess whether the email domain exists and is configured to receive emails.

Although we’ll save a verification tool deep dive for another blog, we do have some tips to keep in mind when choosing your provider:

• Accuracy and Reliability: Look for a tool with a reputation for high accuracy in email verification. Check customer reviews and testimonials to ensure it consistently provides reliable results.
• Validation Methods: Verify what methods the tool uses for email validation. Ideally, it should perform syntax checks, domain verification, and mailbox ping tests to ensure comprehensive verification.
• Data Security and Compliance: Prioritize tools that prioritize data security and comply with privacy regulations. Ensure that your data remains protected and that the tool doesn't retain or share your subscriber information.
• Integration and Compatibility: Consider whether the tool seamlessly integrates with your existing email marketing platform or CRM system. Compatibility will make the verification process more efficient and streamlined.
• Batch and Real-time Verification: Choose a tool that offers both batch verification for large lists and real-time verification for immediate checks during sign-ups or data collection.
• API and Automation: If you require frequent verifications or have a large volume of data, opt for a tool with robust API capabilities and automation features to simplify the verification process.
• Pricing and Plans: Compare pricing models and plans offered by different tools. Consider factors like the number of verifications allowed, pay-as-you-go options, or monthly subscriptions that fit your needs and budget.
• Customer Support: Ensure the tool offers reliable customer support, including access to documentation, FAQs, or a responsive support team to assist you whenever needed.
• Additional Features: Some email verification tools offer extra features, such as duplicate removal, domain blacklisting, or integration with marketing automation platforms. Assess if these features align with your requirements.
• Free Trials or Demos: Take advantage of free trials or demos offered by the tool to test its performance and interface before committing to a long-term subscription.

How to Deal with Inactive Email Addresses

Inactive email addresses may be dormant (and worth removing from your email list) but some of them may be salvageable. This is where email re-engagement campaigns come in. Once you’ve segmented the inactive emails you wish to target for re-engagement, you should create dedicated campaigns to reactivate these subscribers.

Consider these elements when crafting your campaigns to maximize your chances of re-engagement:

• Personalization: Use personalized content and dynamic elements to show subscribers that you value their preferences and understand their needs.
• Win-Back Offers: Provide special win-back offers, such as discounts or freebies, to encourage inactive subscribers to return and make a purchase.
• Survey and Feedback: Send a survey or feedback request to understand why subscribers disengaged and gather insights for improving your content or email frequency.
• Opt-Down Options: Offer the option for subscribers to opt-down their email frequency, allowing them to receive fewer emails instead of unsubscribing completely.
• Use Humor and Creativity: This may be an opportunity to flex some wit! Inject humor and creativity into your re-engagement campaigns to stand out and capture the attention of inactive subscribers.

Check out these 10 tips for writing strong email subject lines and preheaders!

Email Maintenance is an Ongoing Process

Remember, email maintenance is an ongoing process that requires monitoring and constant re-adjusting. Set a regular schedule for email verification and validation — we recommend validating and verifying before major email campaigns, after new list imports, or at the very least, once per quarter.

OneSignal – An Email Platform Built to Cooperate

We know finding the right email provider is a nuanced process and one you shouldn’t be rushed in to. However, if you’re at the stage where you’re ready to start trying email marketing platforms, we have one we think you’ll fall in love with.

OneSignal’s email platform is a low-cost, high-engagement solution for businesses ready to make their mobile messaging an omnichannel powerhouse. With a no-code email composer and the freedom to create custom user journeys, we encourage you to give it a try – no commitment required.