What are the best tools for monitoring and fixing email deliverability issues, considering budget constraints?
Michael Ko
Co-founder & CEO, Suped
Published 30 May 2025
Updated 19 Aug 2025
7 min read
Navigating the world of email deliverability can feel like a maze, especially when your emails aren't landing in the inbox. It's frustrating to invest time and effort into campaigns, only to have them disappear into the spam folder. Understanding what's going wrong is the first step, and thankfully, various tools can help diagnose and address these issues. The challenge often lies in finding effective solutions that align with your budget.
This guide will explore different types of email deliverability tools, ranging from free and low-cost options perfect for smaller operations or initial diagnostics, to more comprehensive platforms designed for larger enterprises. We'll also cover the crucial role of best practices, as tools primarily identify problems, while strategic actions truly resolve them. The goal is to equip you with the knowledge to make informed decisions and improve your email performance, regardless of your financial constraints.
Using free and low-cost tools
For many, budget is a primary concern, but that doesn't mean you're without options. There are several highly effective free and low-cost tools that can provide foundational insights into your email deliverability status. These are excellent starting points for identifying common pitfalls and ensuring your basic configurations are sound.
One of the most valuable free resources available is Google Postmaster Tools. If a significant portion of your audience uses Gmail, this tool is indispensable. It provides data on your domain's reputation, spam rates, IP reputation, and DMARC, SPF, and DKIM authentication statuses. Monitoring this regularly can help you catch issues early. Complementing this, you can use free blocklist checkers to see if your sending IP or domain is listed on any public blacklists (or blocklists), which can severely impact delivery.
For quick content and spam score checks, tools like Mail-Tester.com are incredibly useful. They analyze your email's content, links, and authentication records, providing a score and specific recommendations to improve inbox placement. These tools are often pay-per-test or offer limited free tiers, making them accessible options for specific campaign troubleshooting. To understand how these basic tools fit into a broader strategy, consider exploring essential tools and practices for email deliverability.
Investing in comprehensive platforms
When budget allows, or if email is a critical component of your business, investing in a comprehensive deliverability platform can provide deeper insights and more proactive monitoring. These platforms go beyond basic checks, offering a holistic view of your sending health across various mailbox providers.
These tools typically offer robust features such as inbox placement testing across multiple email service providers (ESPs) (e.g., Outlook, Yahoo, Gmail), spam trap monitoring, and competitive intelligence. They provide detailed analytics, allowing you to pinpoint exactly why emails might be going to spam or promotions folders. Platforms like SparkPost (which acquired eDataSource) are known for their comprehensive offerings in this space, providing deep dives into your sender reputation and campaign performance. For more on advanced monitoring, check out our guide on all-round deliverability tracking.
These higher-tier solutions often come with higher price tags, but they offer unparalleled visibility and often save significant time in diagnosing complex deliverability issues. They are particularly beneficial for businesses that send high volumes of email or for whom deliverability directly impacts revenue. It's a trade-off between cost and the depth of insight and automation provided.
Specialized tools for diagnosis and prevention
Beyond general monitoring, several tools specialize in specific aspects of email deliverability, offering targeted solutions for common problems. These can be integrated into your workflow, either as standalone checks or as part of a larger strategy.
DMARC monitoring tools are essential for domain security and ensuring legitimate emails are authenticated. Tools offering DMARC monitoring provide digestible reports from mailbox providers like Google and Yahoo, helping you understand authentication failures and detect spoofing attempts. Setting up a DMARC record and analyzing its reports is a critical step for modern email sending. For more on this, read about recommended tools for DMARC report analysis.
Another specialized area is email validation and list hygiene. Tools like Kickbox help clean your email lists by identifying invalid, risky, or spam trap addresses before you send, significantly reducing bounce rates and protecting your sender reputation from potential blocklists. Remember, while these tools diagnose, the ultimate fix lies in adopting good sending practices and making informed decisions about your email strategy.
Beyond the tools: strategies for deliverability
While tools are invaluable for monitoring and diagnosing, they don't magically fix deliverability issues on their own. The data and insights provided by these tools must be acted upon through diligent application of best practices and strategic adjustments to your email program. It's about combining technology with smart sending.
Key practices include maintaining a clean and engaged subscriber list, segmenting your audience effectively, and crafting relevant content. Authentication protocols like SPF, DKIM, and DMARC are fundamental, and tools help verify their correct implementation. Regularly checking your blocklist status and responding quickly to any listings is also vital. Ultimately, a strong sender reputation is built on consistent positive engagement and adherence to email sending guidelines. For a deeper dive into why emails fail, refer to our expert guide to improving email deliverability.
The combination of reliable tools and sound email marketing practices is the most effective approach. Tools provide the what and where of deliverability issues, while your strategic decisions and execution address the how. It is a continuous cycle of monitoring, analyzing, and adapting to ensure your messages consistently reach their intended audience. You can dive deeper into common email deliverability issues and their resolutions.
Views from the trenches
Best practices
Implement DMARC with a p=none policy initially to gather data before moving to quarantine or reject. This helps identify unauthorized sending.
Regularly clean your email list by removing inactive or bouncing addresses. This improves engagement rates and sender reputation.
Monitor your sender reputation using free tools like Google Postmaster Tools. This helps you identify potential issues proactively.
Authenticate all your outgoing emails with SPF, DKIM, and DMARC. This is fundamental for modern email deliverability.
Segment your audience and personalize content to improve engagement and reduce spam complaints. Relevant emails get delivered.
Common pitfalls
Relying solely on email service provider (ESP) deliverability metrics, which can often be limited and not show the full picture.
Ignoring DMARC reports, missing critical insights into authentication failures and potential domain misuse.
Not regularly checking blocklists (blacklists) for your sending IPs or domains, leading to unexpected delivery failures.
Purchasing email lists, which often contain spam traps and invalid addresses that damage sender reputation.
Sending emails with generic or spammy content that triggers spam filters and reduces inbox placement.
Expert tips
Tools are diagnostics. They tell you where the fire is. You need a strategy to put it out and prevent future fires.
Focus on the root causes of deliverability issues rather than just treating symptoms. Address list quality, content, and authentication.
Don't be afraid to make tough decisions, like removing unengaged subscribers, even if it means a smaller list. Quality over quantity.
Continuously test your email setup, from authentication to content, across different mailbox providers to ensure consistent deliverability.
Engage with the email community and stay updated on changes from major mailbox providers. This helps in proactive adjustments.
Marketer view
A marketer from Email Geeks says that if budget isn't an issue, eDataSource (now SparkPost) is a really strong choice for comprehensive deliverability monitoring.
2021-12-28 - Email Geeks
Marketer view
A marketer from Email Geeks says that for those on a tight budget, Inbox Monster offers a viable solution for email deliverability monitoring.
2021-12-28 - Email Geeks
Charting your path to inbox success
Improving email deliverability is an ongoing process that benefits from both technological assistance and strategic human oversight. Whether you're working with a limited budget or have the flexibility to invest in premium solutions, a combination of tools and best practices will be your strongest ally. Start with foundational free tools to establish a baseline and address immediate concerns.
As your needs grow, consider more specialized or comprehensive platforms that offer deeper analytics and automation. Remember that no tool is a magic bullet; the data they provide empowers you to make informed decisions about your email strategy, list hygiene, and content. By staying vigilant and adaptable, you can significantly improve your inbox placement and ensure your messages consistently reach your audience.
Outlook, 
Yahoo, Gmail), spam trap monitoring, and competitive intelligence. They provide detailed analytics, allowing you to pinpoint exactly why emails might be going to spam or promotions folders. Platforms like SparkPost (which acquired eDataSource) are known for their comprehensive offerings in this space, providing deep dives into your sender reputation and campaign performance. For more on advanced monitoring, check out our guide on all-round deliverability tracking.
