
Email providers maintain a reputation scoring for email sender domains. A good domain reputation means that your emails are likely to be delivered to the recipient's inbox and are not going straight to the spam folder.

> A damaged domain reputation is hard to fix. You want to avoid this at all costs.

What do you need to do to damage your sender reputation:

### (1) Send big email campaigns to people who didn't subscribe to your email lists

Those people will very likely mark your emails as spam. Spam complaints hurt your domain reputation.

### (2) Send lots of emails to unknown mailboxes

This is also perfect to destroy your domain reputation. Having lots of bounces is a good indication that you have a messy email list. You look like a spammer and this will be reflected in your domain reputation.

### (3) Send emails nobody opens

Sending emails with low engagement is a good indication that your emails are not interesting to the recipients. ESPs take metrics like opens and clicks into account.

### (4) Get lots of unsubscribes

Having frequent unsubscribes to your emails is also a good indication that your emails are considered spam.  

### (5) Send emails to spam traps

Sending emails to spam traps is an effective way to damage your domain reputation. Spam traps are accounts set up by Internet Service Providers that look like normal email addresses. Sending an email to one likely gets you on a blacklist. It's a good indication that you have an unmaintained email list or even scrawled the web for email addresses.

## How to check your domain reputation?

[**Google Postmaster Tools**](https://postmaster.google.com) gives you insights into how Google's email system sees you.

The [Get started with Postmaster Tool](https://support.google.com/mail/answer/9981691?hl=en) guide from Google is a good starting point to explain the basics.

Postmaster Tool provides insights into the following topics:

-   Spam Rate
-   IP Reputation
-   Domain Reputation
-   Feedback Loop
-   Authentication
-   Encryption
-   Delivery Errors

For Domain Reputation Google shows four categories:

-   **Bad** - your domain is known to send high volumes of spam emails. All emails are rejected or marked as spam.
-   **Low** - known as sending spam frequently and emails are likely marked as spam.
-   **Medium** - known as a good sender, but are occasionally marked as spam by some recipients. Emails from such a domain have a good deliverability rate, but an increased spam level can cause some penalties.
-   **High** - Very low spam rate and good reputation. Mails from such a domain will rarely be marked as spam from the spam filter.  

**[Senderscore.org](https://senderscore.org/)** gets information from various ISPs and filtering companies and compute a score between 0 - 100 for sender IPs. It's not available on the domain level though. If you have dedicated IPs, it's absolutely worth monitoring your sender score. Email Providers use the score for their mail filtering decisions.  

## How to improve your domain reputation?

To improve and maintain a good domain reputation, you can take action on the following three levels:

### (1) Technical Level

Make sure to use all domain authentication features correctly:

-   [SPF](https://en.wikipedia.org/wiki/Sender_Policy_Framework) (Sender Policy Framework) to set rules who can send emails for your domain
-   [DKIM](https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail) (DomainKeys Identified Mail) lets recipient systems check that the mail was authorized by the sending domain by using a digital signature.
-   [DMARC](https://en.wikipedia.org/wiki/DMARC) (Domain-based Message Authentication, Reporting and Conformance) to protect domains from email spoofing.

Use services like [MX Toolbox](https://mxtoolbox.com/) to check your technical configuration and get advice for improvement.

### (2) Email Content

Make sure you send emails that are relevant to your target audience. Sending emails with low engagement, high unsubscription or even spam rates do damage to your sender reputation. Use double opt-in in your sign up forms to send only emails to people who actually care about your emails.

### (3) Mailing list cleaning & segmentation

Segment your email lists by engagement and slow down sending emails to people with little to no engagement. Remove emails from your list at some point if they never interact with your emails.

Use an Email Validation Service to clean your email lists from undeliverable emails (bounces), temporary email addresses and risky email addresses.

if you don't use an email validation service yet, [signup now](https://campaignkit.cc/early-access) and try CampaignKit's email validation service for free.

A damaged domain reputation is hard to fix. You want to avoid this at all costs. What do you need to do to damage your sender reputation?

Marco R.

5 Ways to Damage Your Domain Reputation


Email Verifier are services that help you to clean your email lists from invalid email addresses (bounces), disposable email addresses, catch-all email addresses and spam traps without sending emails.

Use our free validation service [CampaignKit](https://campaignkit.cc) for single email addresses to test such a service and learn how it can help you. [Sign Up](campaignkit.cc/early-access) to get access to bulk email validation to clean your entire email list.

The benefit of email validation services is the fact, that you can clean your email lists without actually sending emails to your audience.

Common best practice in email marketing is to segment your audience based on engagement and filter our emails with very low engagement to reduce the risk of getting flagged as spam or even hitting spam traps by recycled email addresses.  

### Why is email validation relevant?

Let's first distinguish between the different types of emails that reach us today:

-   Transactional emails from SaaS services like email verification for a sign up, password reset, emails about changes to the terms of services and other service relevant emails
-   Informational or newsletter emails are sent to an audience who subscribed to an email list. This includes emails such as product or company updates.
-   Cold outreach emails are usually used in sales. Depending on the country you can send emails to people without an opt-in. Usually used in b2b sales, by curating a list of possible leads.

Look at the first type of **emails send by SaaS services.** You offer free accounts and have a high number of possible emails in your system.

You want to prevent users from signing up with disposable emails or putting spam trap emails in your signup form that will blacklist your sender IP. This can have an impact on other users of your system too since your transactional emails might be blocked by their email system.

Verify new emails during signup using an email validation service using an API or plugin. [Read more](https://cms.campaignkit.cc/getting-started-email-validation-api/) about how to use CampaignKit's API to integrate email validation into your existing system.

You send **informational emails** like product updates to your user base. Companies are likely using catch-all email addresses with low engagement. Some of the accounts might be created with disposable email addresses which could cause high bounces. To protect your sender reputation, qualify your target email list by removing such email addresses before hitting send.

Another use case is verifying your curated list for **cold outreach**. Before starting to contact your curated list, make sure to verify the email addresses. Again it's all about protecting your sender reputation and cold outreach is a good candidate to cause damage to it. People are more likely to mark you as spam. One piece of advice: Never buy an email list on the internet.  

### How does email verification work?

Email verifier apply a couple of tests to an email address without sending an actual email:

1.  Domain validation - does the domain exist.
2.  Mail server validation - does the domain have an email server that accepts emails
3.  Mailbox validation - does the email server knows the mailbox.
4.  Disposable email detection - is the email address from a temporary email address provider
5.  Catch-All email detection - is the email address from a common catch-all account
6.  Spam trap detection - detect spam trap email addresses. This can never be 100% accurate though. Even if some providers claim it.

With email verification services you can instantly remove invalid and low-quality email addresses from your email lists.

![Email Validation Result](https://cms.campaignkit.cc/content/images/2022/02/image.png)

Email Validation Result

The example above shows the results of CampaignKit's [free single email verifier](https://campaignkit.cc). In this case, the email verifier verifies that the email address is valid and emails will be delivered. It also detects the catch-all characteristic of the email address. The email address gets a lower scoring.

### TL;DR

If you're looking for a way to clean your contact lists to protect your sender reputation, Email Verification Tools help you to remove invalid and low-quality email addresses from your lists.

But keep in mind to always follow best practices and never send emails that are considered spam to your audience. Email Verifier are an effective way to clean your data, but are not replacing common best practices.

Ready to use an Email Verification Service? Try it out and [sign up for a free trial](https://campaignkit.cc/early-access).

Email Verifier are services that help you to clean your email lists from invalid email addresses (bounces), disposable email addresses, catch-all email addresses and spam traps without sending emails.
Use our free validation service CampaignKit for single email addresses to test such a service and learn how it can help you. Sign Up to get access to bulk email validation to clean your entire email list.
The benefit of email validation services is the fact, that you can clean your email lists wi

Email Verifier - Validate and Clean email addresses


Use CampaignKit's WordPress plugin to validate and tag your new contacts with invalid email addresses in FluentCRM.

The plugin uses CampaignKit's [Email Validation API](https://cms.campaignkit.cc/getting-started-email-validation-api/) to perform the following validations:

-   Domain checks - is the email domain available and accepts email traffic
-   Mailbox deliverability checks - does the target domain accepts emails for the given mailbox
-   Catch-all email address detection
-   Disposable email address detection

This works for all contacts that you add manually or import using the import function.

![](https://cms.campaignkit.cc/content/images/2022/01/image-6.png)

Contact with invalid email address tagged with "Email invalid (2)" in FluentCRM

## Setup Guide

The installation process is simple and consists of three simple steps:

1.  Download Plugin
2.  Add Plugin to WordPress
3.  Configure Plugin

### (1) Get the CampaignKit Word Press plugin

The source code of the plugin is available via [GitHub](https://github.com/campaignkit-cc/wp-plugin). On the release page, you find the [latest version](https://github.com/campaignkit-cc/wp-plugin/releases/tag/v1.0.0) of the plugin.

Click the following button to get a direct link to the latest version.  

[Download the plugin](https://github.com/campaignkit-cc/wp-plugin/releases/download/v1.0.0/campaignkit-wp-plugin.zip)

![](https://cms.campaignkit.cc/content/images/2022/01/image-11.png)

### (2) Add Plugin to your WordPress

Go to your WordPress Admin panel and click **_Plugins_** on the left navigation bar.

You see the plugin page with a list of installed plugins.

![](https://cms.campaignkit.cc/content/images/2022/01/image-7.png)

WordPress - Plugin Page

Click the _**Add New**_ button and click _**Upload Plugin**_. The upload section appears. Click **_Browse ..._** and choose the plugin's zip archive [campaignkit-wp-plugin.zip](https://github.com/campaignkit-cc/wp-plugin/releases/download/v1.0.0/campaignkit-wp-plugin.zip) you downloaded in the previous step.  

![](https://cms.campaignkit.cc/content/images/2022/01/image-8.png)

WordPress - Upload Plugin

Follow the instructions on the screen and click **_Activate Plugin_**. Now the plugin is installed and activated.

![](https://cms.campaignkit.cc/content/images/2022/01/image-12.png)

WordPress - Plugin Page

### (3) Plugin Configuration

ℹ️

The plugin will not perform any email validation until the configuration is done.

To use the plugin, add the API key and select the Tag you want the plugin to add to your contact's with invalid email addresses.

Go to the Settings page (Settings->General) and scroll down to the CampaignKit section.    

![](https://cms.campaignkit.cc/content/images/2022/01/image-10.png)

WordPress - CampaignKit setting

#### API Key

Use your CampaignKit API Key.

##### If you don't have an account yet

Create a new account [here](https://campaignkit.cc/pricing).

#### FluentCRM Tag

Choose a tag the plugin should add to new contacts with invalid email addresses.

To create a new tag go to FluentCRM->Contacts. The new tag can then be selected from the settings page.

![](https://cms.campaignkit.cc/content/images/2022/01/image-13.png)

FluentCRM - Create a new tag

### Done

The plugin will now tag new contacts with invalid email addresses.

Do you need help with the plugin or want to submit a feature request? - use the [GitHub Issue Tracker](https://github.com/campaignkit-cc/wp-plugin/issues).

Guides

Email Validation for FluentCRM


You crafted a beautiful email newsletter with a super engaging subject line and clear call to action, but still, the success of your email campaign is not as good as you wanted it to be.

A high number of bounces harm your email marketing performance. They cause a decreasing sender reputation which impacts the number of emails that hit the recipient's inbox.

Not only bounces can be a problem. Sending to spam traps, frequent complaints and low engagements also harm your sender reputation.

## How to keep an email list in shape?

The best option is to **send an opt-in email** once a new prospect gives you an email address. This validates the existence of the email address and also helps your marketing emails to get delivered to the prospects inbox instead of promotion or spam.

Segment your email list by engagement and **remove emails with no engagement over time**.

Sending opt-in emails is not always possible. You might have an existing email list or emails were collected offline.

**Email Verification Tools** help you to clean and maintain a high-quality email list. Such tools apply a comprehensive list of verifications to the email address to make sure the email address is safe to use for email marketing.

There is a wide number of Email Verification Tools or Email Checkers. Here is a list of commonly used tools:

1.  [CampaignKit](https://campaignkit.cc)
2.  [ZeroBounce](https://zerobounce.net)
3.  [DeBounce](https://debounce.io/)
4.  [Emailable](https://emailable.com)
5.  [Bounceless](https://www.bounceless.io/)
6.  [Xverify](https://www.xverify.com/)

## Why should I use an Email Verification Tool?

1.  **Bounce rates** harm your sender reputation. Detect and remove bounces early from your email lists
2.  **Email addresses can become invalid**. Even with an opt-in an email address can become invalid over time and will bounce.
3.  **Temporary email addresses** shouldn't be used for email marketing and be removed from your email list
4.  **Protect your sender reputation** to make sure your emails get delivered to the recipient's inbox.
5.  Fever dead emails mean **better insights** into your audience through open and click rates.
6.  Fewer people on your list can save you money and **improve your Return on Invest (ROI)**

## How do Email Verification Tools work?

![Email Verification Process](https://cms.campaignkit.cc/content/images/2022/01/CampaignKit-EmailValidationProcess.png)

**Syntax Checks** verify that the email address has a valid email address format pattern. A simple but effective check.

**Domain checks** verify that the domain of the email address exists. Furthermore, a valid SMTP Server is configured (MX records) to accept emails. The domain will be checked against blacklists like [spamhaus.org](https://spamhaus.org) to make sure it's not abused.

**Mailbox deliverability check** verifies that the recipient's mailbox is known by the SMTP server. For the verification, the verification service tries to send an email but aborts the sending process. During the sending process, SMTP servers usually reveal if the mailbox exists or not.

**Catch-All email address detection** gives you a quality score for the email address. Catch-All email addresses have usually a low engagement and higher complaint rate. Common catch-all email addresses are sales@, contact@, postbox@ etc. Some email servers are also configured to route all emails to a single mailbox.

**Disposable email address detection** finds email addresses from disposable email services. Verification tools providers maintain lists of domains used by disposable email address providers. Disposable email addresses are ranked lower. You should avoid them for email marketing.  

**Spam Trap detection** is the most difficult one. Spam traps are email addresses that are used by ESPs and blacklist providers to detect Spam.

Spam traps can be **pristine email addresses** that are specially created for that purpose and published on websites. If you hit such an email address is a very high chance to get blacklisted since this is highly suspicious.

Another form of Spam Trap has **recycled email addresses** that are not existing anymore. Hitting such a Spam Trap comes usually not with high penalties like pristine email addresses, but could harm your sender reputation over time.  

**Domains with typos** (e.g. gnail.com instead of gmail.com) can also be a form of Spam Trap and could damage your sender reputation over time. It's a sign of low-quality email lists.

## How to integrate Email Validation Services?

Most Email Validation Services or Email Checkers provide a Web UI to upload and validate email lists.

Upload a CSV or text file with your email addresses and get a report that gives you some insights.

Here is a simple example report from [CampaignKit](https://campaignkit.cc). You get an overview of your email list's quality. In the table, you see all the validation details including a quality score for each email address.

All the details can be downloaded as a CSV file.

![](https://cms.campaignkit.cc/content/images/2022/01/image.png)

Sample Email Deliverability Report from CampaignKit

### Using an API

Another option is to use an API that allows the integration of an email validation service into your existing tools and workflows by a developer.

[CampaignKit](https://campaignkit.cc) provides an API for Email Address Validation. You can find out more in our [Getting Started Guide](https://cms.campaignkit.cc/getting-started-email-validation-api/). Our [API](https://campaignkit.cc/docs/) is also available via the [RapidAPI](https://rapidapi.com/campaignkit-campaignkit-default/api/campaignkit-email-validation) platform.

Some services provide integrations for email marketing tools like [Mailchimp](https://mailchimp.com/), [Mailjet](https://mailjet.de/) or [ConvertKit](https://convertkit.com), that can be used out-of-the-box. Those integrations can monitor your contact lists without doing manual export/imports of your contact lists.

## Conclusion

Regular Email Address Verification should be in every marketer's toolbox. It helps you to protect your sender score and improve your marketing performance.

Try our [Email Validation Tool](https://campaignkit.cc) to clean our email list today.

Email Verification Tools help you to clean and maintain a high-quality email list. Such tools apply a comprehensive list of verifications to the email address to make sure the email address is safe to use for email marketing.

How to clean your Email List? - Email Verification Tools


💡

You need to [signup](https://app.campaignkit.cc/api/signup) for an account to get access to the Email Validation API.

The Email Validation API allows you to validate a list of email addresses and to retrieve detailed validation results.

## Getting started

Start with a simple validate query for a list of email addresses. Use the API key from your account.

```
curl --request POST \
 --url 'https://api.campaignkit.cc/v1/email/validate' \
 --header 'Authorization: Bearer <<your API key>>' \
 --data '{ "emails": ["a348sf@gmail.com"] }'
```

This validates a single email address and returns the result.

## Response

The Email Validation API returns a result object for each email address in the request.

```
{
    "results": [
        {
            "email": "a348sf@gmail.com",
            "result": {
                "syntax": "pass",
                "mx": "pass",
                "mailbox": "fail",
                "score": 0,
                "description": [
                    "mailbox"
                ]
            }
        }
    ]
}
```

### Can I use the email address?

If the **score is greater than 2** you can use the email address and emails will most likely not bounce.

A **score of 2** identifies email addresses that will be delivered, but the email address is a SPAM Trap or temporary email address.  

### Result

Element

Values

Description

syntax

pass, fail

Email syntax check result.

mx

pass, fail

MX record lookup result. Checks if the domain exists and publishes information about an email server

mailbox

pass, fail, n/a

Mailbox check result. Checks if the email server can be reached and tries to verify if the email address exists. Returns `n/a` if the mailbox cannot be verified.

### Score

The score range goes from 0 to 10 where 0 identifies an email that is guaranteed to not be usable and 10 means that all checks passed and emails will be delivered to a personal email address.

Score

Description

**0**

Email will bounce

**2**

Email can be used, but looks like a SPAM Trap or temporary email address.

**9**

Email looks good, but mailbox couldn't be verified.

**10**

Email address passed all checks and emails will be accepted by the server.

### Description

The description contains additional information about the check results and resulting score.

Value

Description

syntax

Email syntax check failed.

domain

Domain doesn't exist or no MX record configured.

mailbox

Mailbox check returned unknown recipient.

verifyRejected

Mailbox could not be verified. The recipient's mail server rejected verification attempts

blacklist

Email address has been detected in local blacklist

disposable

Email address or domain has been detected as temporary email address.

catchall

Email address has been identified as a common catch all address.

## References

-   Documentation: [https://campaignkit.cc/docs/](https://campaignkit.cc/docs/)

The Email Validation API allows you to validate a list of email addresses and to retrieve detailed validation results.

CampaignKit Blog

5 Ways to Damage Your Domain Reputation

Email Verifier - Validate and Clean email addresses

Email Validation for FluentCRM

How to clean your Email List? - Email Verification Tools

Getting Started with the Email Validation API