Imagine after sending marketing emails to thousands, if not millions of prospects, but your emails fall in the spam folder or not reach your prospects’ mailbox at all. Obviously, this can influence your email marketing in a negative way. And your marketing attempts will be worthless. But email marketing doesn’t have to be daunting. Therefore email testing tools are here to help you in getting rid of those errors and build you a successful campaign.

Actually, there are plenty of free tools online that can help you to test spam score, deliverability, as well as the rendering of your email. These tools can be the key to your success. In this post, I’ve featured 6 best email testing tools to help you a run spam test on email subscribers.

1.Sender Score

Sender Score is a free tool powered by ReturnPath. It measures the reputation of your IP addresses on a scale from 0 to 100. When your score is higher, then your reputation is better as well as your email deliverability rate is higher. The numbers are computed on a rolling 30 days average and giving you where your IP address ranks in competition with other IP addresses. In addition, ReturnPath has a Blocklist Lookup tool that allows you to check if any of your IP addresses have been blacklisted.

2. Litmus

Litmus is one of the best spam testing tools that offer a free trial. But the duration of the free trial is short. It only lasts for 3 days. However, within this short period of time, you can benefit too. Their services are really good. It has spam testing functionalities that are as part of its platform. Litmus tests email addresses against the significant spam filters. Not only that, but it also makes actionable suggestions that can help you to correct the errors. Their tool is also incorporated with Campaign Monitor and MailChimp.

3.Email on Acid

Email on Acid spam testing is similar to Litmus. It has a test feature that checks emails against 23 of the most popular spam filters along with the most common blacklist services. But this feature is only accessible when you subscribe to the whole platform. You can then test with Email on Acid whenever you work.

4.Mail Tester

Mail Tester is a free tool to check your spam scores. What you just do is to send an email to their email address. Then the tool calculates your spam score. It calculates based on DKIM, your SPF record, keywords in your letter, and on whether you are blacklisted or not. Mail Tester works with any type of emails even though they typically focus on newsletters.


Postmark is a free spam check tool. It helps to assess the content of your emails and produce actual scores. It also evaluates on whether your email copy contains spam words. After evaluation, it grades your content and makes the suggestion of words that you’re supposed to use. Furthermore, they also have a lightweight JSON API that you can use to your platform for checking spam scores.


GlockApps is one of the best email testing tools available online. It only takes something like 2 minutes to check your spam rate. For at least 3 campaigns, you can freely use this tool. It also provides with most important information such as your sender score and notifies you if you’re on any blacklist. And it collects all unwanted information and monitoring all the email addresses that it provided as well as suggestions on what you should improve.

Brief Statement About These Testing Tools

These tools have almost similar features. Most of them give you an email list of approximately 80 email addresses. Mostly those emails will be not of the same email provider. It can be AOL, Yahoo, Gmail,  iCloud, and many more. To such a great extent, you can pick whatever you want.

Let’s use GlockApps as an example. For a dropshipper using Klaviyo, you just go to the report of email campaigns and click/tap advanced reports, it will show the actual ratio of different email domains that are used by people in your list. Then you load those email addresses and GlockApps provides you with a code to encapsulate into your email. After that, you send out the email and GlockApps collects all unwanted information and monitoring all the email addresses that it provided.


If you’re serious about growing your business, make sure to have at least one email testing tool. You never know your email issues if you don’t test your emails before sending them. Therefore it is important to use spam testers to prevent your emails from getting to the spam folder. There is no struggle to use any of those tools as they are automated and built into your account.

And they fully show how your email will look like into your clients’ mailbox. Again you’ll be ensured that it displays as expected in your subscriber’s mailbox. Finally, email testers can detect the issues that can cause your emails to be unsuccessful and give you greater results.