Top 7 Email Spam Checker Tools 2025
If your emails are landing in spam folders, you're not alone. In 2025, advanced filters make email deliverability more challenging than ever. To ensure your messages reach inboxes, spam checker tools are essential. These tools analyze your email content, sender reputation, and technical setup to identify issues before sending. Here are 7 of the best spam checker tools to help improve your email campaigns:
- Warmforge: Automates email warm-ups and monitors sender reputation. Starts at $9/month per mailbox.
- MailGenius: Focuses on content optimization with detailed spam analysis. Plans begin at $29/month.
- GlockApps: Offers spam filter testing and inbox placement insights. Pricing starts at $79/month.
- SpamAssassin: Free, open-source tool for tech-savvy users.
- SendForensics: Provides unlimited spam tests and reputation monitoring. Plans start at $49/month.
- Postmark Spam Check: A free, web-based tool for quick spam analysis.
- Mail-Tester: Free daily tests with paid plans starting at $9.90/month.
Each tool offers unique features tailored to different needs, from small businesses to large-scale campaigns. Below is a quick comparison to help you decide.
Quick Comparison
| Tool | Starting Price | Free Option | Key Feature | Best For |
|---|---|---|---|---|
| Warmforge | $9/month (annual) | 1 free slot + test | Email warm-up + spam checking | Reputation management |
| MailGenius | $29/month | Limited trial | Content optimization | Marketing campaigns |
| GlockApps | $79/month | 7-day trial | Inbox placement testing | Enterprise deliverability |
| SpamAssassin | Free | Yes (full access) | Open-source spam filtering | Tech-savvy users |
| SendForensics | $49/month | None | Unlimited spam tests | Deliverability monitoring |
| Postmark | Free | Yes (unlimited) | Simple spam analysis | Basic checks |
| Mail-Tester | $9.90/month | 3 free daily tests | Detailed spam reports | Regular testing needs |
Tip: Start with free trials or basic plans to find the tool that works best for your email strategy.
1. Warmforge
Warmforge is an email deliverability platform designed to enhance sender reputation and ensure your emails land in primary inboxes. By automating warm-up processes and monitoring with AI, it helps you optimize your campaigns before they even begin. Let’s dive into its standout features and pricing options.
Spam Detection Accuracy
To improve inbox placement, Warmforge uses real-world testing by sending emails to actual Gmail and Outlook accounts. Depending on your plan, it monitors between 50 and 250 mailboxes per test, providing real-time placement insights. Additionally, it conducts essential checks like DNS, MX, and blacklist monitoring to keep your emails on track.
Pricing and Affordability
Warmforge offers flexible pricing tailored to different needs. Plans start at $9 per mailbox slot per month, with discounts for annual billing (up to 57% savings). For bulk purchases, the price drops to $3 per slot. Each user gets one free warm-up slot and one placement test every month. The Pro Plan, priced at $32.50 per month (billed annually), includes 100 tests, while the Growth Plan provides unlimited tests for $140.80 per month.
Integration Capabilities
Warmforge integrates seamlessly with The Forge Stack tools, including Salesforge, Mailforge, Infraforge, Primeforge, and Leadsforge - though each requires its own subscription. It also works with Google Workspace and Microsoft 365. Notably, users with a Salesforge subscription gain access to unlimited warm-up features, making it a valuable addition for multi-channel outreach efforts.
Ease of Use for Technical and Non-Technical Users
Managing email deliverability is straightforward with Warmforge. Simply connect your email accounts, and the platform’s AI takes care of the warm-up process automatically. The always-on warm-up feature ensures your accounts remain in top condition, even during campaign pauses. The user-friendly dashboard provides clear insights into deliverability metrics, making it accessible for non-technical users while offering advanced analytics for those who want to dive deeper into DNS health and placement data.
2. MailGenius
While Warmforge automates email warm-up to improve deliverability, MailGenius focuses on refining email content before you hit send. It’s an email testing tool designed to analyze your campaigns for potential spam issues and offer actionable feedback to enhance deliverability. Unlike warm-up tools, MailGenius works as a pre-send analysis platform, helping you optimize both your email content and technical setup to meet strict spam filter standards.
Spam Detection Accuracy
MailGenius puts your emails through their paces using multiple spam filters, including SpamAssassin and Barracuda, as well as algorithms that mimic those used by major email providers. It evaluates over 25 spam-related factors, such as subject line wording, content structure, image-to-text ratios, and sender authentication protocols.
The platform assigns a spam score from 0 to 10, where lower scores indicate a higher likelihood of reaching the inbox. Detailed feedback highlights problematic areas like excessive capitalization, flagged keywords, or missing authentication records. While MailGenius excels at content analysis, it doesn’t test inbox placement with real accounts, so it’s best used alongside other tools for a complete strategy.
Pricing and Affordability
MailGenius uses a credit-based pricing system, starting at $29 per month for 100 email tests. For those needing more, the Standard plan is $49 per month for 300 tests, and the Professional plan costs $99 monthly for 1,000 tests. Unused credits roll over, making it a practical choice for businesses with fluctuating email volumes.
If you’re new to the platform, there’s a free trial that includes 3 email tests - no credit card required. Agencies or high-volume senders can opt for custom enterprise pricing, which offers bulk discounts to lower the cost per test.
Integration Capabilities
MailGenius works seamlessly with popular email service providers like Mailchimp, Constant Contact, Campaign Monitor, and SendGrid via API. It also supports direct email forwarding, allowing users to send test emails to a unique MailGenius address for quick analysis.
Although it doesn’t natively integrate with warm-up tools like Warmforge, both platforms can complement each other. MailGenius handles content optimization, while warm-up services focus on building sender reputation.
Ease of Use for Technical and Non-Technical Users
MailGenius is designed with simplicity in mind, offering a user-friendly interface that requires little to no technical expertise. Users can paste their email content or forward a message for analysis, receiving detailed reports in just minutes. Results are presented in plain, easy-to-understand language, with color-coded warnings and actionable suggestions for improvement.
The platform also provides guidance on fixing SPF, DKIM, and DMARC issues. For non-technical users, the explanations of spam triggers are clear and approachable, while developers can dive into more detailed technical recommendations to fine-tune their email infrastructure.
3. GlockApps
After Warmforge and MailGenius, GlockApps steps up with a powerful mix of spam filtering and real-world inbox performance testing. It combines spam filter analysis with inbox placement testing across major email providers, giving you a clear picture of where your emails end up - whether it’s the inbox, spam folder, or promotions tab. This makes it a great tool for businesses looking to fine-tune their email strategy both before and after sending.
Spam Detection Accuracy
GlockApps runs your emails through more than 30 spam filters, including well-known ones like SpamAssassin, Barracuda, and SpamTitan. It also conducts inbox placement testing with real seed accounts across platforms like Gmail, Outlook, Yahoo, and Apple Mail. This approach gives you actual placement data instead of just theoretical spam scores.
The platform breaks down filter flags and explains why they’re triggered. It tests key authentication protocols like SPF, DKIM, and DMARC, while also analyzing your content and sender reputation. Emails are scored on a scale from 0 to 100, with lower scores indicating better deliverability. GlockApps also tracks your sender reputation over time, helping you spot and address any trends that could hurt your campaigns.
Pricing and Plans
GlockApps offers three main pricing tiers:
- Starter Plan: $79 per month, includes 1,000 spam tests and 100 inbox placement tests.
- Professional Plan: $159 per month, includes 5,000 spam tests and 500 placement tests.
- Agency Plan: $399 per month, includes 25,000 spam tests and 2,500 placement tests.
Each plan supports unlimited users, and there’s a 7-day free trial to test things out. Custom enterprise options are also available for larger needs.
Integration Options
GlockApps integrates seamlessly with email service providers like Mailchimp and SendGrid via API or SMTP. You can automate testing by forwarding emails to a unique GlockApps address or use their Chrome extension for quick checks.
Additionally, webhook notifications keep you informed about deliverability issues in real time. When paired with warm-up tools like Warmforge, GlockApps provides the insights needed to monitor and improve email performance over time.
User Experience: Simple Yet Detailed
GlockApps strikes a balance between in-depth analytics and a user-friendly dashboard. Results are displayed in easy-to-read, color-coded charts that show inbox placement rates for different providers. Non-technical users can quickly understand if their emails are reaching inboxes, while technical teams can dig deeper into reports that highlight specific filter triggers and authentication errors.
For troubleshooting, the platform includes step-by-step guides to help you fix SPF records, improve content scoring, and address reputation issues. Email previews let you see how your messages appear across various email clients, making it easier to optimize formatting and design. Most users find they can navigate the core features within minutes.
4. SpamAssassin
SpamAssassin is a trusted open-source spam filtering engine that's been around for years, widely relied upon by email providers and businesses. Unlike automated tools like Warmforge, SpamAssassin demands hands-on configuration, making it a favorite among tech-savvy users who prefer full control.
Spam Detection Accuracy
SpamAssassin uses a scoring system to evaluate emails against a wide variety of predefined rules. Each rule adds or subtracts points based on spam-like characteristics, and emails that score above a certain threshold (commonly 5.0) are flagged as spam. It checks for things like suspicious subject lines, odd formatting, and questionable links. Its Bayesian filtering also learns from email patterns over time, improving its ability to separate legitimate emails from spam. For advanced users, there’s even the option to create custom rules, adding an extra layer of flexibility. This powerful detection system offers a cost-effective way to combat spam.
Pricing and Affordability
SpamAssassin is completely free to download, install, and customize, making it a budget-friendly solution for startups, small businesses, and developers who have the technical know-how to set it up. However, its free nature comes with a catch - it requires technical expertise for installation and maintenance. For organizations without an IT team, managed hosting services are available, providing support and handling upkeep for a monthly fee.
Integration Capabilities
SpamAssassin is designed to work seamlessly with a variety of email systems, thanks to its compatibility with standard protocols like SMTP and POP3. Email servers such as Postfix, Sendmail, and Exim come with built-in support for SpamAssassin, simplifying the integration process for experienced administrators. This adaptability has made it a staple in many email security setups.
Ease of Use for Technical and Non-Technical Users
For technical users and system administrators, SpamAssassin offers a high level of control and transparency. You can review detailed scoring reports, tweak rules to fit specific needs, and integrate it with existing monitoring tools. However, it’s not the most user-friendly option for those without technical skills. Installation usually involves command-line work and manual configuration of text files, as the standard version doesn’t include a graphical interface. To bridge this gap, many organizations pair SpamAssassin with front-end tools that simplify tasks like managing quarantined messages and adjusting settings, combining its powerful spam detection with improved usability.
5. SendForensics
SendForensics is an email deliverability platform designed to provide marketers with detailed insights through unlimited spam tests, inbox placement evaluations, and comprehensive DMARC reporting. Its robust suite of tools makes it a go-to option for email marketers looking to optimize their campaigns.
Spam Detection Accuracy
One of SendForensics' standout features is its unlimited spam testing, offered across all pricing tiers. This allows users to test their emails against a variety of spam filters before launching campaigns, ensuring they avoid potential pitfalls. Additionally, the platform’s inbox placement tests help identify whether emails land in the primary inbox or get sidetracked into folders like spam or promotions. The ability to preview emails across different clients and devices further ensures campaigns look polished everywhere. These tools not only enhance email performance but also come bundled with competitively priced plans.
Pricing and Affordability
SendForensics offers flexible subscription plans tailored to different needs:
- Brand Plan: $49/month ($39/month when billed annually) for 2 domains and 2 users.
- Company Plan: $79/month ($63/month annually) for 5 domains and 5 users.
- Agency Plan: $199/month ($159/month annually) for 15 domains and 10 users.
- Enterprise Plan: Starting at $349/month, with customizable options.
All plans include a 14-day free trial, and annual billing comes with a 20% discount. These tiers make it accessible for businesses of all sizes, from small teams to large agencies managing multiple clients.
Integration Capabilities
SendForensics enhances its value with seamless integration options. All plans support native integrations, allowing businesses to connect the platform with their existing email marketing tools. For enterprise users, the optional Enterprise SAML/SSO add-on ensures secure single sign-on functionality, making it easier to align with corporate identity systems. The ability to manage multiple domains from a single dashboard is especially appealing for agencies juggling multiple client accounts.
Ease of Use for Technical and Non-Technical Users
The platform features a web-based dashboard designed to accommodate both technical and non-technical users. Unlike command-line tools like SpamAssassin, SendForensics presents data through intuitive visual charts and straightforward reports. While users new to email deliverability may face a slight learning curve, it’s far less daunting compared to open-source alternatives, making it a practical choice for teams with varying levels of expertise.
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6. Postmark Spam Check
Postmark Spam Check is a free, web-based tool designed to provide quick and straightforward spam analysis. Unlike platforms that require subscriptions or registrations, this tool offers instant results without any cost, making it a practical choice for businesses that only need occasional email testing or are working within a limited budget.
Spam Detection Accuracy
This tool evaluates emails based on specific spam filter criteria, delivering a clear score along with concise explanations. It examines factors like the quality of the subject line, sender reputation, HTML structure, and content patterns that might trigger spam filters. While it doesn't offer the extensive testing features of premium tools, it effectively highlights common issues that could land emails in spam folders.
One standout feature is its real-time feedback system, which pinpoints potential problems such as overly promotional language or missing authentication records. However, it lacks inbox placement testing across different email clients, which limits its scope compared to more advanced tools. Even so, the immediate insights it provides are a valuable asset for improving email deliverability.
Pricing and Affordability
Postmark Spam Check is completely free to use. This makes it especially appealing for small businesses, startups, or individual marketers who need basic spam analysis without any financial investment. Its cost-free model makes it an excellent supplementary tool to use alongside paid platforms, offering essential functionality without added expenses.
Integration Capabilities
This tool functions as a standalone web application, meaning it doesn’t have native API integrations. Users must manually copy and paste their email content or HTML code into the interface for analysis. While this manual process may not match the automation of platforms like Warmforge, it ensures compatibility with a variety of email creation workflows. For those seeking a budget-friendly option, this manual approach provides a simple yet effective way to check for spam issues.
Ease of Use for Technical and Non-Technical Users
Postmark Spam Check is designed with simplicity in mind. Its clean and intuitive interface doesn’t require any technical expertise. Users can simply paste their email content into the text box, hit "Analyze", and get instant results. The insights are clear and actionable, helping users improve their email deliverability over time without any steep learning curve.
7. Mail-Tester
After using Postmark Spam Check for a basic spam analysis, Mail-Tester offers a more in-depth look at email spam detection. It's a go-to tool for those seeking detailed evaluations of email authentication, content quality, and technical configurations. Plus, it's free to start, making it a popular choice for marketers and small businesses.
Spam Detection Accuracy
Mail-Tester evaluates emails using a 10-point scoring system, covering key areas like SPF, DKIM, DMARC, HTML quality, image-to-text ratio, and blacklist status. It checks if your domain is flagged by major blacklists such as Spamhaus, SURBL, and URIBL. Additionally, it reviews your email's HTML structure, pinpointing issues like broken links, missing alt tags, or overly promotional language - factors that can trigger spam filters.
What sets Mail-Tester apart is its detailed reporting system. Instead of a simple pass-or-fail result, it breaks down each element impacting your spam score. You’ll get clear explanations about why certain issues might hurt deliverability, along with tailored recommendations. This makes it easier to focus on the changes that will have the greatest effect on improving inbox placement.
Pricing and Affordability
Mail-Tester operates on a freemium model, allowing up to 3 email tests per day for free. If you need more, paid plans start at $9.90 per month for 1,000 tests. The free daily limit resets every 24 hours, ensuring regular access to the platform’s core features.
For businesses focused solely on spam analysis rather than broader deliverability tools, this pricing is much more budget-friendly compared to enterprise solutions like Warmforge.
Integration Capabilities
Mail-Tester keeps things simple by requiring users to forward emails to a unique testing address. This approach ensures compatibility with any email client or automation system, without the need for complex API setups.
While it doesn’t offer automated monitoring or advanced API integrations like some high-end tools, its straightforward design makes it accessible to users of all technical skill levels. The manual testing process pairs well with the platform’s clear, actionable guidance.
Ease of Use for Technical and Non-Technical Users
One of Mail-Tester's standout features is its user-friendly design. Complex technical data is presented in a way that's easy to digest, using color-coded results and plain-language explanations. Critical issues are flagged in red, warnings in yellow, and successful checks in green, helping users quickly identify and prioritize fixes.
To get started, all you need to do is send your email to the provided testing address. Within minutes, you’ll receive a detailed report with step-by-step recommendations. This simplicity makes Mail-Tester an excellent choice for marketing teams that need quick, actionable insights without requiring deep technical knowledge. Whether you’re looking to fine-tune a single campaign or overhaul your email strategy, Mail-Tester provides the guidance you need to make impactful improvements.
Feature and Price Comparison
This section breaks down the key features and pricing of each tool, helping you align your choice with your email strategy.
Warmforge offers a blend of automated warm-up and spam checking at $9 per mailbox per month (billed annually). It includes AI-powered warm-up, placement tests, health checks, and blacklist monitoring. Users get one free Google or Microsoft mailbox slot and a free placement test each month, making it a strong option for maintaining email reputation over time.
MailGenius caters to marketing teams with its detailed spam analysis and content optimization suggestions. With pricing from $29 to $99 per month depending on testing volume, it’s ideal for teams running frequent campaigns and needing regular performance insights.
GlockApps stands out with its expansive testing capabilities, checking deliverability across more than 20 email providers at once. Starting at $79 per month, it’s tailored for enterprises and agencies managing multiple campaigns, offering in-depth inbox placement data and authentication testing.
SpamAssassin is a free, open-source choice for users with technical expertise. While it requires server setup and maintenance, it allows unlimited testing without subscription fees, making it a practical option for those comfortable with technical configurations.
SendForensics emphasizes reputation monitoring and blacklist checking. It’s priced between $49 and $199 per month, appealing to businesses focused on recovering from deliverability challenges or maintaining consistent oversight. (Note: SendForensics does not offer a free plan.)
Postmark Spam Check delivers a simple, no-cost solution for basic spam analysis. Perfect for small businesses and individual marketers, it provides essential spam detection tools without any associated fees.
Mail-Tester balances features and affordability, offering 3 free tests daily and paid plans starting at $9.90 per month for 1,000 tests. It provides detailed scores and actionable recommendations, making it a budget-friendly choice for regular testing.
| Tool | Starting Price | Free Option | Top Feature | Best For |
|---|---|---|---|---|
| Warmforge | $9/month (annual) | 1 free slot + monthly test | Integrated warm-up and spam checking | Email reputation management |
| MailGenius | $29/month | Limited trial | Content optimization | Marketing campaigns |
| GlockApps | $79/month | 7-day trial | Multi-provider testing | Enterprise deliverability |
| SpamAssassin | Free | Yes (full access) | Open-source flexibility | Technical users |
| SendForensics | $49/month | None | Reputation monitoring | Deliverability recovery |
| Postmark | Free | Yes (unlimited) | Simplicity | Basic spam checking |
| Mail-Tester | $9.90/month | 3 daily tests | Detailed reporting | Regular testing needs |
When choosing the right tool, consider your testing frequency and feature needs. If you’re an occasional user, free daily limits might suffice. However, high-volume senders or businesses with complex requirements may need tools that offer unlimited testing or advanced features. The best solution will provide flexibility for your current operations while accommodating future growth.
Conclusion
When selecting an email spam checker, it's essential to match the tool with your specific needs, budget, and technical expertise. For those just starting out or sending emails occasionally, free tools like Postmark Spam Check and Mail-Tester are great starting points. However, if you're managing high-volume email campaigns, you'll likely need a more robust solution.
Different tools cater to different user profiles. For example, SpamAssassin offers free, unlimited testing for tech-savvy users, while MailGenius provides marketers with in-depth analysis. On the enterprise side, GlockApps delivers multi-provider testing for comprehensive insights.
One standout option is Warmforge, which combines spam checking with automated warm-up services. At $9 per mailbox per month (billed annually), it uses AI to simulate human behavior, helping maintain your sender reputation. Plus, it includes a free slot for Google or Microsoft mailboxes and a monthly placement test, giving you a chance to evaluate its performance before committing.
To find the best fit for your workflow, start with free trials or basic plans. Consider factors like testing limits, the level of reporting detail, and how well the tool integrates with your existing email setup. Ultimately, choose a solution that can grow alongside your business, providing the insights you need to keep your emails landing in inboxes.
FAQs
What should I consider when selecting an email spam checker tool for my business?
When choosing an email spam checker, prioritize features that directly affect your email deliverability. These include email content analysis, domain reputation checks, and authentication protocol validation. These elements ensure your emails have the best chance of reaching your audience. Additionally, consider tools that are user-friendly, provide dependable customer support, and align with your budget - especially if your team isn't highly technical.
While free tools can offer basic insights, premium solutions often provide deeper analysis and greater accuracy. For example, platforms like Warmforge go a step further by including features such as email warm-up and deliverability monitoring. These extra capabilities make them a well-rounded choice for boosting the success of your email campaigns.
How does using an email warm-up tool like Warmforge alongside spam checker tools improve email performance?
Using an email warm-up tool like Warmforge alongside spam checker tools can make a noticeable difference in how your emails perform. Warmforge works by mimicking natural email activity, which helps your messages bypass spam filters and land directly in recipients' primary inboxes. This process not only improves deliverability but also strengthens your sender reputation over time, making it more likely that your emails will be opened and read.
When combined with spam checker tools, which scan your email content for elements that might trigger spam filters, you get a comprehensive approach to email optimization. These tools ensure your emails are both engaging and compliant with spam filter standards. Together, they form a smart strategy to boost your email campaigns and improve outreach success.
Are there any free tools to check for spam and improve email deliverability?
Yes, there are free tools available to help you assess spam risks and improve email deliverability. Some popular options include Unspam.email, MailReach, GlockApps, BetterMerge, MailGenius, and Folderly. These tools analyze key factors like email content, sender reputation, authentication protocols, and potential spam triggers to help your emails land in inboxes rather than spam folders.
While free tools can be quite useful, they often come with limited features or less detailed analysis. If you're after a more in-depth solution, platforms like Warmforge might be worth exploring. Warmforge offers advanced features such as automated email warm-up, deliverability monitoring, and placement tests. Plus, they provide one free warm-up slot and a placement test each month, giving you a chance to test their capabilities without any upfront cost.