Top MXToolbox Alternatives for Email Deliverability in 2026

Many cold-outreach users rely on MXToolbox for DNS lookups, blacklist checks, and basic infrastructure troubleshooting. It’s a dependable starting point for identifying technical issues but it also falls short in several critical areas. 

Despite its 4.1/5 rating, MXToolbox is not a comprehensive solution for teams that need deliverability visibility.

If you’re looking for capabilities like inbox placement testing, sender-reputation signals, spam trigger analysis, and support for B2B cold email infrastructure, MXToolbox alone won’t be enough. 

Modern email programs require tools that go beyond DNS validation and provide real visibility into how mailbox providers treat your messages.

In this blog, we break down where MXToolbox excels, where it falls behind, and which alternatives offer stronger features for deliverability, cold outreach, and performance monitoring.  

What to Look for in an MXToolbox Alternative?

When evaluating MXToolbox alternatives, focus on solutions that address the realities of B2B cold outreach. The best platforms provide insights into how mailbox providers handle your emails, as well as DNS record validation. Key features to prioritize include:

• Warmup programs designed specifically for B2B cold email: Choose email warmup platforms that use Google Workspace and Microsoft 365 environments to generate consistent positive engagement signals. These platforms help build your sender reputation safely and effectively for B2B campaigns.
• Authentication checks for SPF, DKIM, and DMARC: Opt for solutions that validate your authentication records (SPF, DKIM, DMARC) during real test sends. This approach confirms your records are correct in reliable sending conditions.
• Visibility into sender reputation trends as sending volume scales: Select tools that track your sender reputation over time, especially as your sending volume increases. This visibility helps you identify and address deliverability issues before they impact your outreach.
• Clear separation between DNS diagnostics and deliverability monitoring: Ensure the platform clearly distinguishes between DNS record validation and deliverability monitoring. This separation helps you track both infrastructure health and inbox performance independently.

TL;DR - Compare the Top MXToolbox Alternatives

Selecting the right deliverability tool depends on your specific requirements, whether you need DNS validation, inbox placement insights, or cold email support. The table below summarizes the core capabilities and ideal use cases of the top MXToolbox alternatives in 2026.

The Best MXToolbox Alternatives in 2026

For teams that require more than basic DNS checks and need actionable insights into inbox placement and sender reputation, choosing the right MXToolbox alternative can make a significant impact in 2026. Below are the top tools, organised by use case, with a clear breakdown of each tool’s features, strengths, limitations, ideal users, and how it differs from MXToolbox.

1. MailReach

MailReach is one of the leading MXToolbox alternatives for B2B and cold-outreach teams. While MXToolbox primarily performs DNS checks, MailReach runs end-to-end deliverability tests that show how mailbox providers classify your emails and surface actionable signals to improve inbox placement and sender reputation over time.

Key Features

• Real inbox placement results: MailReach’s spam tester evaluates emails comprehensively, including SPF, DKIM, DMARC validation, along with inbox placement outcomes across mailbox providers. Instead of relying on static DNS lookups, these tests surface reputation signals inferred from inbox vs spam placement, giving a more accurate view of deliverability than DNS-only tools like MXToolbox.
• Gmail and Outlook inbox placement testing: With MailReach, you can test where your emails land across major mailbox providers (for example, Gmail and Outlook). 
• Email warmup using a peer-to-peer network: MailReach’s warmup feature routes warmup traffic through professional Google Workspace and Microsoft 365 inboxes. Rather than simulating sending behavior, it creates natural, human-like engagement patterns between professional inboxes, which is how Gmail and Outlook infer sender trust for B2B email. This helps build domain reputation safely and progressively for cold outreach.
• Accurate SPF and DKIM validation: MailReach validates SPF and DKIM within a full spam test, producing more reliable results than isolated DNS checks. This ensures your records are validated in real-world sending conditions.​ 

Pros 

• Provides inbox-placement results rather than DNS-only data
• More accurate SPF/DKIM validation due to full sending context
• Solves cold email deliverability, a gap MXToolbox does not address

Limitations

• Not a DNS monitoring tool or uptime-tracking tool  (complements MXToolbox but does not replace it)
• Not designed for infrastructure or network outage monitoring

Best For

• B2B teams
• Cold outreach teams
• Google Workspace or Outlook environments
• Teams requiring actionable inbox-placement insights

Pricing

2. GlockApps

GlockApps is a strong alternative for email marketers and deliverability teams who need diagnostic visibility into inbox placement across multiple mailbox providers such as Gmail, Outlook, Yahoo, and regional ISPs. The platform specializes in seed list–based testing, allowing users to observe where emails land across mailbox providers under controlled test conditions.

Key Features

• Seed list testing across global ISPs: GlockApps enables users to test inbox placement with seed lists, providing visibility into deliverability across major and regional providers. This provides comparative inbox-placement diagnostics across ISPs, rather than DNS-level validation.
• Content analysis: GlockApps analyzes email content for spam triggers and technical issues, helping users optimize their messages for better inbox placement.
• Spam filter scoring: GlockApps offers spam filter scoring, combining SpamAssassin and proprietary algorithms to identify risk factors that could affect deliverability. Though, these factors do not represent mailbox-provider reputation or guaranteed inbox outcomes.

Pros 

• Provides seed-based inbox placement diagnostics across many mailbox providers, including regional and local ISPs (for example, French and German providers)
• Clear dashboards for reviewing inbox vs spam outcomes across providers

Limitations

• Not designed to build or stabilize sender reputation for cold outreach
• Seed-based testing reflects diagnostic outcomes, not ongoing inbox trust
• Does not offer email warmup or engagement-based reputation building

Best For

• Email marketers and cold-outreach teams who need mailbox-provider insights and detailed inbox-placement data 

Pricing

GlockApps offers a freemium model with a free tier for basic inbox placement and spam-filter testing. Paid plans provide expanded seed lists, more frequent testing, and advanced analytics, with prices starting from $99/month for small business users.

3. GMass Email Deliverability tester

The GMass Email Deliverability Tester provides focused Gmail deliverability testing and tab classification checks. It reports where emails land in Gmail (such as Primary, Promotions, Updates, or Spam), making it useful for Google Workspace administrators and marketers who want to observe Gmail-specific placement.​

GMass’s tester is helpful for seeing how Gmail classifies emails, but it does not improve inbox placement or stabilize sender reputation for cold outreach. It also does not offer Outlook or Microsoft 365 visibility, warmup capabilities, sender reputation monitoring, or cross-domain or multi-provider diagnostics, so it is best suited for Gmail-only analysis rather than broader deliverability or cold email programs.

Key Features

• Tests Gmail delivery: The tool verifies inbox placement across all Gmail tabs, helping teams understand how Gmail categorizes their messages based on content and sending patterns.
• Best for Google Workspace: It is optimized for Google Workspace environments, making it suitable for teams that primarily send email through Gmail and want Gmail-specific classification insights.

Pros vs MXToolbox

• Provides real Gmail tab classification visibility, which MXToolbox does not offer
• Useful for diagnosing Gmail-specific placement patterns

Limitations

• Limited to Gmail only; no Outlook or Microsoft 365 visibility
• Does not provide cross-provider inbox diagnostics
• No warmup or engagement-based reputation building
• Does not surface sender reputation signals beyond Gmail classification outcomes

Best For

• Google Workspace administrators and IT teams
• Email senders seeking granular Gmail tab-classification and inbox-placement insights

Pricing

 The GMass Email Deliverability Tester is a free tool that anyone can use, with no GMass account or paid subscription required. It is separate from GMass’s paid email-sending plans, which cover campaign features, tracking, and automation inside Gmail.

4. Google Admin Toolbox

Google Admin Toolbox helps Google Workspace administrators validate DNS records and verify email authentication. It runs SPF, DKIM, and DMARC checks, making it ideal for teams responsible for Google Workspace email configurations.​

Key Features 

• SPF, DKIM, and DMARC validation: Runs comprehensive checks to ensure your Google Workspace domains are configured with email authentication settings, reducing delivery failures caused by misconfiguration.
• DNS diagnostics for Google Workspace: Provides domain-specific DNS lookups and detailed error reporting tailored to Google’s infrastructure, helping teams quickly identify and resolve misconfigurations.
• Platform-specific troubleshooting: Offers connectivity tests and configuration checks aligned with Google Workspace best practices, simplifying root-cause analysis for email delivery issues.

Pros 

• Offers deeper DNS logs and more granular insights for Google Workspace domains
• Tailored for Google Workspace, providing platform-specific diagnostics and troubleshooting

Limitations

• DNS-first tool only; does not provide inbox placement visibility or reputation signals
• Not designed for cold email outreach or broader deliverability diagnostics

Best For

• Google Workspace administrators
• Teams that require robust DNS validation and authentication monitoring for Google Workspace domains

Pricing

Google Admin Toolbox is free for Google Workspace administrators and provides DNS validation and email authentication checks as part of the Workspace suite.

5. Postmark Tools

Postmark Tools are designed for Postmark customers who need reliable DNS validation for DMARC and SPF records. These tools help users verify authentication settings, improving deliverability.​

Key Features

• DMARC and SPF record validation: Postmark Tools help users verify DMARC and SPF records, ensuring correct email authentication for improved deliverability.
• Configuration dashboard: Provides a centralized interface for managing DNS settings, authentication records, and troubleshooting within Postmark.

Pros 

• Provides detailed DNS logs and validation, often with additional context for Postmark users
• Tailored for Postmark’s platform, offering specific insights and troubleshooting for Postmark users
• Free for Postmark users

Limitations

• Uses a DNS-first approach; it does not offer inbox placement or sender reputation diagnostics
• Not designed for cold-email workflows and lacks broader deliverability testing such as seed-list testing, content analysis, and spam-filter scoring 

Best For

• Postmark teams (developers, ops, and administrators) requiring reliable DNS validation and authentication monitoring

Pricing

Postmark’s tools are free for Postmark users and include DMARC and SPF lookups as part of their email service.

6. Mailgun

Mailgun provides DNS checking and detailed sending logs so teams can validate DNS records and analyze sending behavior (bounces, delivery errors, volume and timing). It is useful for teams using its service to validate domain authentication (SPF, DKIM, DMARC), monitor sending logs and delivery metrics (bounce rates, delivery errors, sending volume), and troubleshoot authentication or delivery issues.​

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Key Features

• DNS checker: Allows users to validate SPF, DKIM, and DMARC records directly within the Mailgun platform, ensuring accurate email authentication
• Detailed sending logs: Provides comprehensive visibility into sending activity, including bounce rates, delivery errors, and volume metrics, enabling users to monitor and troubleshoot email campaigns
• Delivery analytics: Provides insights into email delivery performance, including timing, volume, and recipient engagement, enabling users to optimize sending strategies

Pros 

• Mailgun provides DNS logs and more detailed sending analytics, giving users a clearer picture of their domain health
• Customized for the Mailgun platform and provides platform-specific insights and troubleshooting for senders

Limitations

• DNS-first tool with no warmup capabilities or features to improve and maintain sender reputation.
• Not optimized for cold email outreach or broader deliverability needs

Best For

Mailgun users needing reliable DNS validation and detailed sending analytics

Pricing

Mailgun’s DNS checker and sending logs are included at no extra cost with Mailgun email service plans.

Which MXToolbox Alternative is Better for Email Deliverability?

MXToolbox continues to be a reliable starting point for DNS and infrastructure validation.

In 2026, a robust deliverability stack combines tools for DNS and infrastructure, inbox placement, and sender reputation management. 

• Use MXToolbox or Google Admin Toolbox for DNS configuration and authentication validation
• Use GMass for Gmail-specific inbox and tab-classification visibility
• Use GlockApps for seed-based inbox diagnostics across multiple ISPs

Modern email deliverability requires inbox placement insights and automated warmup sequences for new sending domains. 

MailReach measures B2B inbox placement across Gmail and Outlook using live test emails and provides insight into reputation signals inferred from inbox outcomes. In addition, MailReach offers:

• End-to-end DNS validation for SPF, DKIM, and DMARC​
• Inbox placement monitoring with free spam tests and alerts​
• Sender reputation monitoring specifically for B2B cold outreach​
• Automated warmup to build, maintain, and repair sender reputation

Explore MailReach to see how it complements or replaces DNS-only tools and when it’s the right choice for B2B cold outreach and deliverability.