How to Test Inbox Placement and Spam Score with GlockApps

There’s no reason to send emails without confidence that they will land in the Inbox.

Email delivery problems can happen at any time when ISPs start sending your emails to the spam folder, or blocking them altogether.

In order to identify and fix delivery problems before they cause significant harm to your business, we recommend running GlockApps Inbox placement and spam filtering tests regularly.

The main difference of the GlockApps email spam checker from simple content checkers for spam keywords is that we require you to send the message to multiple “seed” email addresses in order to check the spam score for your email content, your reputation (reputation of the email/domain you send from), authentication and real email placement across dozens of ISPs. It’s important that you send a test email from the same place you’ll send your actual campaign from.

GlockApps connects directly with Mailchimp to spam test an email. It is also possible to test any other email independently of the email provider you use. You need to take a few extra steps to do this.

So, if you are NOT using Mailchimp, follow these simple steps to test the campaign and determine email delivery problems before you send to your real email list:

1. Create Email Test

Login to your G-Lock Apps account.

Click the Start Test button.

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Choose the spam filters and the Internet service providers you want to test your email with. We recommend that you test your email with all available providers and spam filters.

Optionally write a note for your test. It helps to identify the test if you create more than one test for the same message and change something in the content or sending infrastructure.

Click Next.

2. Send Message to the Seed List

Copy the ID string.

The ID string is unique for each test. The ID lets our system identify the email you send to the seed list, so the outcome (whether it lands in the Inbox, Spam Folder, or never arrives at all) can be linked back to your GlockApps test report.

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Go to your email client, create or open the message and paste the ID at any place in the message body or in the Subject line.

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Go back to GlockApps and copy the seed list.

You can select a separator for the email addresses on the seed list: comma, semicolon, line break, line break with comma, and line break with semicolon to copy the seed list in the format supported by your email system or email service provider.

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Load the seed list into a new list in your email marketing software, application or ESP or paste the seed list into the To field.

Send the message with the ID string to the seed list.

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Be sure to use the same method that you normally use when emailing your real mailing list, whether this is from your private email server, an ESP (Email Service Provider), or from a personal email account such as Gmail or Hotmail.

This way your delivery test results will be accurate since you’re reproducing the same conditions as when you email your real mailing list (both email content and sender reputation matter!).

3. See the Result: Report Data Explained

Click “View Report” and watch the results pour in on the delivery test’s page, in real-time.

What the Report Items Mean

When the test is completed, the full deliverability report gives you the data under three tabs: Deliverability, Content Analysis, and Suggestions.


The Deliverability tab gives you the information about your sender infrastructure (SPF, DKIM, HELO to IP, sender score), spam score and email placement.

At the top of the Deliverability tab, there is a diagram that shows the percentage of the messages that went to the Inbox, Tabs, Spam folders or were not delivered (missing) to the seed email addresses.

The Tabs rate shows the percentage of the messages that went to a tab in the Inbox, not to the general Inbox. It’s like the Promotions tab at Gmail or Newsletter tab or Commercial tab.

The Missing rate is the percentage of the messages that did not reach the test mailboxes. It could be because the sending system did not send them or because the receiving server blocked or rejected the message.

Sender Authentication

In the Sender Authentication section, you can see if your authentication records SPF, DKIM, rDNS and HELO to IP passed or failed. Authentication records are important for deliverability and must be set up correctly. Strong email authentication increases the chance of the email to be delivered to the Inbox.

You can activate the DMARC Inspector in your account, generate and publish a DMARC record in your sending domain’s DNS and get the DMARC data: DMARC compliant and non-compliant sending sources and number of messages sent by each source. You’ll see whether or not all of your legal sources send properly authenticated emails and you will be notified if your DMARC compliance rate drops and DMARC fails.

Sender Score

In the Sender Score section, you see the score of your sending IP address according to Return Path. GlockApps checks your sender score at The higher the sender score, the better for deliverability. However, a high sender score doesn’t guarantee the Inbox placement. What is more important is the reputation of the sending domain and the sending IP address with the particular mailbox provider.

When you send the emails from shared IP address(es), the sender score is calculated based on all messages sent by all the users sharing the IP. You don’t have much control over the sender score for shared IP addresses. If you send from a dedicated IP address, then you control all of email campaigns and the impact they have on the sender score. If the sender score for your dedicated IP is low, go to and look at the detailed report to know which things had the biggest impact on the sender score. You’llwant to address those issues.

IP Black Lists

By clicking on the Black Lists section, you can see where your sender’s IP address is listed. GlockApps checks your sender’s IP address against dozens of the most known blacklists and gives you the report where your IP is listed and where it’s not. You can follow the provided links to the blacklists’ websites and read more information about your IP listing. It makes sense to remove the IP address from blacklists if you use a dedicated IP address. If you send from the ESP’s shared IP addresses, you are not in control under the IP reputation.

You can determine whether or not blacklists impact your ability to deliver emails or not with the GlockApps Bounce Monitor. The Bounce Monitor will track and show you all your bounce emails. It will categorize them for you: hard bounce, soft bounce, FBL (user complaints), blocks, etc. You can see the statistics for each sender. When an email is blocked, it bounces back and falls into the Block category. So, you can go to that category and read the bounce error descriptions. If a message bounced because of the IP listing, it will be shown in the bounce error description. If your dedicated IP is blacklisted, you can then go to the blacklist’s site and look for the de-listing process. If a shared IP is blacklisted, then you can report this issue to your email service provider.

Domain Black Lists

This section appears in the report only when GlockApps finds the links with blacklisted domains in your message content. GlockApps checks the domains you use in the links in the message against domain blacklists and reports you the detected listings. It can also be domains in target links if you use redirects. You can go to the blacklist’s website and look for the de-listing process.

Spam Filters

GlockApps also runs your message against the spam filters such as the Google Spam filter, Barracuda and SpamAssassin. You can see the result for each filter in the report.

Not only does GlockApps show you the email spam score, it also explains why you got that score. It points you to the issues related to the message HTML code, images, links, and content. This advice helps you adapt your email’s content to improve delivery and open rates.

While Barracuda and SpamAssassin give the detailed report about how they assign the spam score, the Google Spam filter does not provide much information why it marked the message as spam and/or phishy. It returns only the final result.

Email Placement

Then goes the email placement with each test email address. You get the report about how your message is treated by the most popular mailbox providers and spam filters such as Amazon WorkMail, Godaddy, Mimecast Email Security, and Network Solutions.

In the Delivered To column, you see the folder where the email was found: Inbox, Spam, Promotions, etc.

In the Sender IP column, you can see the IP address from which the message was sent to that particular email address. Often times, email service providers use a pool of shared IP addresses which change from message to message.

In the SPF column, you can see the SPF record check by the appropriate ISP. Sometimes, some ISP cannot resolve SPF and you can see the fail result. Looking at the SPF column you can get the idea if the SPF fails for all providers and it is the issue at your end or the SPF fails for some particular provider and the issue is the provider’s side.

In the Sender Score column, you can see the sender score for the IP address shown in the Sender IP column.

The Blacklists column shows whether or not the sender IP is blacklisted. You can click on the IP address and see a more detailed report about blacklists.

The Delivered In column shows the time the delivery to the destination email address took. It helps estimate how fast your email system sends emails and how fast the recipient’s provider accepts the messages from you. Often times, the delivery takes hours because the receiving server throttles emails from the sender’s IP address because of the low IP reputation.

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If you click on the three-dot icon at the right side, you can select the “View Headers” or “View IP Details” option.

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The message headers can shed some light on why the message went to the spam folder. In particular, the Authentication-Results header field shows if all email authentication records passed or not. The X-Microsoft-Antispam header for Microsoft accounts shows the Bulk Complaint Level (BCL) and Spam Confidence Level (SCL) that impact the email placement with the Hotmail and Outlook providers.

Selecting “View IP Details”, you can see the IP address status against blacklists. If it’s blacklisted, you’ll get the URL of the blacklists where you can go and search for the removal instructions (again, it makes sense if you are sending from a dedicated IP address that you control).

Content Analysis

Under the Content Analysis tab, you can see the information about your message size and content. GlockApps tells you whether or not there are issues with your HTML code, links, images and text.

In case the system detects any issues with your HTML code, you can click the “Open Template Editor” button, clean up your code and download the fixed HTML. The Template Editor will fix the majority, but not all, HTML issues.

Spam filters can be triggered if you have dead links in the message, or if you have too many links and/or images in the content. The content analysis helps you optimize your message and make it pass through spam filters which increases the chance of the message to land in the user’s Inbox.

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Action Steps

Under the Action Steps tab, you can read the tips and recommendations for you to improve your Inbox rate. The action steps are given based on the information GlockApps extracts from the message headers, content, spam filters reports, and email placement.

If the GlockApps report does not show any apparent issues but the messages are filtered as spam, it makes sense to test different things to isolate the issue. Test different content, email templates, with/without links and images, different From email addresses/domains and even different email service providers. Often times, the problem may be in the reputation of the sender IP and/or domain.

You can find more tips on how to test and find deliverability issues in these articles:

How to Find and Fix Email Deliverability Issues
How to Troubleshoot Inbox Placement

4. Waiting for Data Test: Delete or Re-Use

Sometimes, you may not receive a deliverability report after clicking the “View Report” button. GlockApps can be showing “Waiting for data” for hours or days.

It happens when you forgot to add the id string to the message and GlockApps cannot associate the message with the test and/or when your email system or email service provider did not send the message to the GlockApps seed list.

What to do with the “waiting for data” test?

You can re-use the “waiting for data” test in order to not lose the credit.

Click on the “Waiting for data” link under Reports, click the button to get the seed list, copy the ID string and paste it in the message.

Re-send the message to the seed list using your SMTP server or ESP.

The credit is not deducted from your account when you re-use the “waiting for data” test.

Or you can delete the “waiting for data” test, get the credit back and create a new test in your account.

When you delete a test with an empty report, our system credits your account with one point that you spent for the test that had not delivered the report.

Is It Possible to Download the Report?

GlockApps does not allow to export or download the report as a PDF, HTML or Excel file.

But you can share the report with other people via the URL. Click the “Share Results” at the right side of the report. The report opens in a new tab in the browser. Copy the link of the shared report and send it to your mail server admin or email service provider or anyone you want to see the report.

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Next to the “Share Results” option, there are the “Get Seed List” and “View Message” options.

Sometimes, GlockApps is not able to provide the complete report because your email system did not send the message to all test addresses or because the receiving server rejected the message from your IP address/domain.

If some data is missing in the report, you can click on the “Get Seed List” button, get the test id and seed list and re-send the message with the id to the seed list. If the message is delivered to all the seed email addresses, the missing data will be shown in the report. Existing data is not updated.

The “View Message” option allows you to view your message content. To view the HTML source, right-click the mouse on the message content and select “View frame source” from the menu.

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Why is It Important to Differentiate the Deliverability Rate and Inbox Rate?

Let’s say your email service provider is reporting 95% deliverability with a 5% bounce rate. It looks like 95% deliverability but it may be 70% Inbox placements and 25% spam placements. So, actually, 25% of your delivered emails did not reach the recipients. And emails that don’t reach the recipients won’t be read.

With time, your spam rate could be increasing and preventing your mail from reaching your subscribers. For some senders, this could mean thousands in lost revenue.

Therefore, you should pay attention to your Inbox placements and take steps to fix delivery issues to maximize your Inbox placement rate.

Delivery duration tracking is also essential. It helps determine if there is an issue with ISP throttling. Rather than blocking your emails altogether, some ISPs will delay the delivery of emails when the volume passes a certain threshold. This can be particularly harmful to time-sensitive promotions or important transaction emails.

We recommend running GlockApps email delivery tests regularly on your campaigns in order to identify and fix delivery problems before they come between you and your email recipients!

Let us know if you have any difficulties!

Important note!

Each ISP or mailbox provider stores information about the sender and outgoing mail servers used to send large volumes of emails to it. They track how the recipients engage with the received emails and over time each sender gains a reputation, good or otherwise. ISPs update their filtering algorithm on a regular basis depending on how they treat the sender at this time. In your GlockApps dashboard, you can see your current sender reputation and know if any of ISPs or popular filters are flagging your email as spam.

If you use any of the below email delivery services to send your email campaigns, check the appropriate tutorial to learn how to use your delivery service with GlockApps:

How to Test a MailChimp Email Campaign
How to Test a MailerLite Email Campaign
How to Test a Benchmark Email Campaign
How to Test an AWeber Email Campaign
How to Test an ActiveCampaign Email Campaign
How to Test a GetResponse Email Campaign

Read also:

How to Test via Dedicated Email Address
How to Find and Fix Email Deliverability Issues


Julia Gulevich is an email marketing expert and customer support professional at GlockSoft LLC with more than 15 years of experience. Author of numerous blog posts, publications, and articles about email marketing and deliverability.