Whether you’re sending emails to cold sales prospects or sending a weekly newsletter to your client list, you need to make sure your emails land in the main inbox.
As email service providers like Gmail and Outlook get more sophisticated at blocking spam, it’s not uncommon for marketing and sales emails — even ones with good intentions — to get caught in the spam filter.
In this guide, I’ll show you some of the best email deliverability tools that will help you understand, monitor, and improve your email deliverability.
Let’s jump right in.
What is an Email Deliverability Tool?
Email deliverability tools improve your chances of landing in the primary inbox.
They include features such as:
Email and inbox warm-up tools to build trust with email service providers
Inbox placement testing to identify where email clients categorize your emails
Inbox configuration monitoring to make sure your technical setup is correct
Email list verification to reduce your bounce rate
There’s no fixed set of features that all of the tools we'll look at in this article have. But, the one thing they do have in common is their main goal: helping you keep your emails out of spam.
Best Email Deliverability Tool for Landing in the Primary Inbox
1. Mailflow: Run Deliverability Tests and Warm Up Your Inbox For Free
Warm up your email inbox, stay out of spam, and see detailed reports on where your emails are landing.
Mailflow is a platform to help you warm up your inbox, check your SPF and DKIM records are in place, monitor email blacklists, and more.
It's available to use for free, despite being just as powerful as the other paid options out there.
Here’s what it can help you with.
Warm Up Your Inbox to Improve Cold Email Deliverability
The best signal to email service providers that you’re a trustworthy sender is engagement: are people opening and replying to your emails?
Mailflow’s email auto warmer automatically sends emails to a network of real email inboxes (made up of other real people also using the platform) and generates engagement by opening and replying to your emails.
If your emails are flagged as spam, they’ll be automatically removed from the spam folder, and replied to — showing the email service providers that your account is trustworthy.
You can warm up 100 email addresses on the free plan, or upgrade and add up to 300 inboxes to Mailflow at once.
Advanced Email Health Monitoring
Mailflow includes tools to help you monitor your inbox health and improve it.
For example, you can identify if your email is on any of 100+ blocklists, and can keep track of your sender reputation across different email service providers which gives you clues into whether or not you can continue running campaigns at the same rate you are currently.
As well as this, Mailflow can check your SPF and DKIM configuration.
If there are problems, you’ll be instantly notified and can make updates so you can send emails with confidence.
Dedicated Support Team to Help Solve Your Key Deliverability Issues
Even with the best email deliverability software, you can still encounter issues.
To help you get through every deliverability challenge you face, Mailflow has a team of dedicated email deliverability experts who you can reach out to at any time for help. This feature is available on paid plans only.
Their team has years of experience solving deliverability problems and can provide the extra support and tips you need to ensure your emails always land in the inbox.
Automatically warm up your inbox for free on up to 100 inboxes or up to 300 on paid plans
See detailed sender and IP reputation reports for the main email service providers on where your emails are landing
Blacklist domain and IP monitoring to identify deliverability risk factors before they cause problems
SPF and DKIM configuration tools to ensure your inbox is correctly set up
Dedicated support team to help you improve email deliverability
Pricing: Mailwarm is completely free for up to 100 inboxes.
9 Alternative Email Deliverability Tools
Test if your emails look like spam to email service providers before you hit send.
Spamtester provides you with a unique test email address that you then send an email to, from your own inbox, with the email template you’re planning to use.
Once you’ve sent your email to the address provided, check your score. Mail Tester will flag any potential problems that could cause you to land in spam.
You’ll see a score, broken down by different areas:
The text and content in your email
Whether your DKIM, SPF, and DMARC records are correct
If your inbox is listed in any email blocklists
Whether you’ve added any broken links in your email
For example, in this email we tested, the issues flagged were empty message and potential improvements to the message.
Once you review any factors that affect your score, you can take action to improve them and re-test.
After you’ve reviewed each result, you can run another test and see if your score improves.
Spamtester won’t improve your email deliverability for you, but it will show you potential factors that are worth improving in your email.
Keep in mind that you don’t need to listen to every suggestion, but they are useful guidelines.
Quickly review every key factor that affects your deliverability
Run email spam tests to identify why your emails aren’t landing in the primary inbox
Review your email copy and templates for spam trigger words
Check if you’re on any email, IP, or domain blocklists. See clear instructions on how to remove your domain from blocklists to stop your emails from being flagged as spam.
Even if you’ve never spammed anyone in the past, the previous owner of your domain may have used it differently
You can use Spamhaus to check if your domain has been listed on any common blocklists, such as Spamhaus’ Domain Blocklist, IP Blocklist, or Exploits Block List.
Spamhaus also provides instructions on removing your domain from any of their blocklists to ensure your deliverability rates return to their usual levels.
If you were responsible for being listed on a blocklist, there’s a lower chance of being removed successfully (at least in the short term), but it's helpful if you’re worried that your domain may have been used in the past to send spam.
Check if your domain is on any blocklists
Understand the reasons you’re on a blocklist
Instructions on how to remove your domain from blocklists
4. Check MX
A free tool by Google to help you review if your technical foundations are in place to ensure good deliverability.
Ignoring the technical setup of your email and domain is a surefire way to get caught in the spam filters.
Check MX is a free tool from Google that lets you quickly review if your technical elements are set up correctly.
Add your domain URL, run a check, and you’ll see a list of factors that can affect your email deliverability, with details on whether or not yours are set up correctly.
It’s worth running your domain through this as soon as you buy it, as ignoring these factors can affect how your emails land even if you’re not sending marketing or sales campaigns at scale.
Check MX is perfect for G Suite users as it directs you to Help Center articles for every issue flagged, but it still works if you use Outlook or another email provider.
Considering it’s completely free to use and doesn’t require you to create an account, there’s no downside to trying it out.
Quickly review if your technical foundations are strong
DKIM, DMARC, SPF, CNAME, and MX Record checking
A suite of deliverability software to help you improve and monitor your email and domain health.
GlockApps offers a range of tools to improve your email deliverability, including bounce analytics to see if your emails are being blocked by ISPs, automatic email deliverability tests, and an ongoing monitoring and alerting system.
It helps improve email deliverability across all of the main email clients you’ll be sending to, including Gmail, Yahoo Mail, Outlook, Apple Mail, and more, thanks to health checks and warnings if your IP or domain is showing problems.
One particularly useful feature for email marketers is the ability to review your HTML templates for ‘risky’ content. You can bring in your template from an email marketing tool of choice, and it will show you any potential problems, such as broken links, code, images with poor formatting, or text issues — all of which could harm your email deliverability.
You’ll need to subscribe to a paid plan, but, if you’re sending your email campaigns to a large list of subscribers and rely on email deliverability to drive revenue, it’s going to be worth the investment.
Understand where in your recipients’ inbox your emails are landing
Check your IP address and send domain against 50+ blocklists.
Useful template editor to review your email content for errors
Ongoing monitoring system to notify you of deliverability problems
6. Sender Score
Understand if the IP address you’re sending emails from is seen as trustworthy or not by mailbox providers.
Sender Score’s free tool lets you check the reputation of the IP address you’re sending emails from. The company says it’s “like gauging your creditworthiness, but for email.”
You’ll see details on:
If your IP is on any known blocklists
Whether or not recipients are reporting you for spam
If ESPs are rejecting or blocking your emails, and why
All in all, it’s a very useful tool.
Like with every deliverability tool, Sender Score looks at general metrics and it’s up to you to fix any problems that come up.
See your overall Sender Score
Check if your IP is on any known blocklists
Check for any spam complaints against your IP address
7. Everest by Validity
Detailed deliverability and email reputation metrics, with insights to help you improve them and identify problem areas.
Everest is an email delivery platform that’s central purpose is to monitor and help you improve your email deliverability, highlight problems when they occur, and give you actionable insights to improve your deliverability rates.
Insights you’ll have access to include:
Percentage of your emails reaching the inbox
Visibility into competitor sending practices
One key feature for anyone sending regular emails to their list is an overview of the times of day your emails tend to get open so you can optimize your campaign send times to land in your audience’s inbox when they’re active.
You’ll need to schedule a demo to get access to the platform, and it’s best for enterprise-level companies. But, if you have the budget and the ROI on improving your deliverability is there, it just might be worth it.
Pricing: Custom based on needs
Integrates with most major email-sending platforms
Insights into sender reputation and key deliverability metrics
Ongoing spam check monitoring and notification system
Identify if your domain is on blocklists or being caught in spam filters
Verify every email in your list to ensure you’re never caught in spam traps and every email is valid.
Low-quality email lists are a major problem. If you buy a list and start sending emails to people on it straight away, it won’t be long before you get caught by a spam trap, or see so many bounced emails that ESPs start to distrust you.
NeverBounce is a useful tool to verify your email list before you reach out to anyone on it.
You can upload your email list, and almost instantly see whether your emails are valid. If not, NeverBounce will remove them, with 99.9% accuracy.
When your list has been verified, you’ll see clear results. Emails will be classed as Valid, Unverifiable, Unknown, Disposable, or Invalid. It’ll be clear whether or not you should risk reaching out to the address.
It also integrates with QuickMail, and you can automatically clean and verify your prospect list from your dashboard.
Once you connect your accounts, you can immediately start verifying emails on your prospect list to give you peace of mind before launching a campaign.
Pricing: Starts at $0.003 per verified email address
Mail server validation to verify if the address is real
Email testing tool to automatically remove duplicate emails in your email list
Integration with QuickMail to verify email validity before sending a campaign
Lightweight email health monitoring tools to troubleshoot issues and verify if your emails will land in the primary inbox.
MXToolbox is a platform containing multiple email health-checking tools. When you’re first getting started, you can use it to analyze whether or not your team’s inboxes are correctly configured. It’ll tell you whether your SPF (Sender Policy Framework), DKIM, and DMarc records are in place, and if not, let you know exactly which ones aren’t.
As well as that, it’ll monitor if your email address is ever added to spam lists, and perform daily checks on the status of your mail servers.
There’s also an email header review tool. After you paste in your email header, which contains technical information about the sender, it’ll make suggestions for improvements and let you know if there are any compatibility risks.
The UI is simple, but MXToolbox is an effective tool once you get the hang of it.
Pricing: Free plan available, paid plans from $129 per month
Ongoing monitoring tools that alert you if your inbox has problems
15+ tests to check your DNS server configuration to eliminate the risk of problems
Email header analyzer to troubleshoot problems with email deliverability or verify the source of your emails
Email deliverability platform to help you predict where your emails will land in the inbox before you send a campaign.
SendForensics’ platform provides email deliverability services to help you with tasks like setting up your email authentication, monitoring your inbox reputation, and even an email copy analyzer that warns you if your template includes spam words or phrases.
There are a couple of useful features. For example, you can run a campaign to a seed list of recipients across different popular email clients like Gmail, Yahoo, and Outlook. If there are problems, you can make adjustments before sending a campaign to your whole list.
As well as that, you can visualize what your email marketing templates will look like in different inboxes, devices, and browsers. That means you can fix your designs before sending them to thousands of recipients and ensure you get the maximum engagement levels possible.
Pricing: From $39 per month
Email template analyzer to verify visual elements look correct across inboxes
Run inbox placement tests to predict deliverability issues before they happen
Real-time monitoring that alerts you if your inbox has issues that could affect deliverability
Improve your email marketing deliverability with a variety of enterprise-grade tools
3 Free Email Deliverability Tools for Quick Fixes
Most tools on our list have a paid tier. However, there are free email deliverability tools that can help you solve the most obvious problems and get your inbox to a point where you can rely on it to deliver your emails.
Here are some of the best free options today:
Mailflow: Warm up 100 inboxes at a time for free
Spamster: Identify configuration and setup fixes to improve your deliverability
Check MX: Free tool from Google to identify potential inbox setup problems
Do You Need an Email Deliverability Tool?
Anyone sending emails for marketing or sales purposes needs to be monitoring their email deliverability.
Reliable email deliverability — that is, landing in the main inbox most of the time - gives your email campaigns the best possible chance of success. Even if you’re sending high-quality emails and are seeing strong engagement levels, over time, you’re not completely safe.
Generating engagement is always an uphill battle, particularly if you’re cold-emailing a list of prospects who don’t know you. If a few of your campaigns see low engagement, you’re opening your email account up to risks such as being blocked by any major email service provider or being forced to regularly buy new domains to send your emails from.
Once those things happen, it can be a vicious cycle that’s difficult to get out of.
Instead, monitor your deliverability on an ongoing basis and you’ll be confident that your emails are landing where you hope they are — in your prospects’ main inbox. If there are potential issues, you’ll know as soon as possible, and can take action to ensure your email deliverability isn’t affected.
The tools we’ve looked at here all require relatively minimal effort to use, and they’ll help you understand where your emails are landing and how you can improve your deliverability.
Can Software Really Improve Email Deliverability?
The email deliverability solutions we’ve looked at aren’t a silver bullet to getting replies to your cold outreach.
What email deliverability tools will do:
Help you understand where your emails are landing in your prospects’ inbox
Give you insights into the reasons for your inbox placement
Show you if there are factors that could negatively affect your campaigns
What email deliverability tools won’t do:
Stop people from deleting your emails
Stop prospects from reporting you as spam
Give you insights into the quality of your prospect list
Use them as part of a cohesive outreach strategy, and don’t rely on them to solve all of your cold email problems.
Remember, Software Can’t Solve Every Deliverability Issue
These tools are all useful for anyone sending email campaigns regularly.
But, remember that the best way to improve your email deliverability is to send emails that get genuine engagement from the people you're reaching out to.
That means every email should be:
Personalized to the recipient
Be genuinely valuable or helpful
Have a call-to-action that encourages a positive response
If you can manage those three things, you’re off to a great start.
If you're looking for more deliverability best practices, make sure to check out our complete guide to email deliverability.
It’s easy to get caught up in testing and evaluating deliverability tools to find the right one for you.
But, the exact email deliverability software you use doesn’t matter as much as your process.
Getting your domain and email address correctly set up
Building a high-quality email list and personalizing your emails
Using a template that doesn’t have compatibility issues with any email client
Once your foundations are in place, you can use a tool like Mailflow to warm up your email address and monitor your deliverability performance on an ongoing basis.
When your email deliverability is at the level you need it to be, you can create your free QuickMail account and start sending cold emails that get replies.