--- title: "MailFlowMonitoring - Free Round-trip Email Infrastructure Monitoring | MailFlow Monitoring" description: "Monitor your email infrastructure with round-trip SMTP and IMAP testing. Detect deliverability issues, server outages, and routing problems before they impact your business." image: "https://mailflowmonitoring.com/images/og-default.png" canonical: "https://mailflowmonitoring.com/" --- Trusted since 2018 · 10,000+ businesses worldwide # Free round-trip SMTP monitoring for businesses that depend on email. Small email delays can be costly. MailFlowMonitoring continuously tests your email infrastructure by sending test emails and tracking responses. Detect issues before they impact your users. [ Start Monitoring Now → ](http://app.mailflowmonitoring.com/users/sign%5Fup) [ View Features ](#features) No credit card 10 min setup First monitor free Trusted by enterprises, SaaS companies, and government 10K+ Businesses 99.9% Uptime 24/7 Monitoring 2018 Since How It Works ## How round-trip monitoring works Continuous testing ensures your email infrastructure is always operational. 1 ### We send test emails Our monitoring endpoints continuously send test emails to addresses you specify in your domain, simulating real email traffic. 2 ### Your server auto-responds Configure your SMTP server to automatically respond to our test emails. We track response times and delivery success. 3 ### Instant alerts on issues If responses fail or exceed your configured thresholds, we immediately alert you via email, SMS, webhook, or PagerDuty. ### What round-trip monitoring validates - MX records are correctly configured for your SMTP servers - SMTP servers and relay software are up and running - Internet connection is active (for self-hosted or co-located servers) - Spam filters are not delaying or blocking legitimate email delivery - Complete email routing path is functioning correctly Capabilities ## Monitor your mail flow Round-trip SMTP and IMAP monitoring with performance metrics and header analysis. ### Round-trip Email Tests Continuous inbound and outbound email tests with complete header analysis and transaction logging. ### Multi-channel Alerts Configurable real-time alerts via email, SMS, webhook, PagerDuty, and Slack when thresholds are exceeded. ### Performance Metrics Track response times, delivery success rates, and historical statistics to optimize mail server performance. ### Customizable Timeouts Configure monitoring intervals and timeout thresholds based on your specific business requirements. ### Transaction Logging Complete log of all test emails sent and received, helping diagnose routing and blacklisting issues. ### 24/7 Monitoring Day and night continuous testing ensures you are alerted to disruptions the moment they happen. ## You're in complete control ### Scalable monitoring Start with one free monitor and scale up as your infrastructure grows. ### Custom intervals Control how often we check your servers, from every minute to hourly. ### Flexible thresholds Set RTT thresholds and delay rates that match your requirements. ### Multi-channel alerts Email, SMS, webhook, PagerDuty, Slack - your channel, your rules. Our Story ## Built by email infrastructure experts As an email service provider, we needed to track mail flow problems through a large number of inbound email servers. Unlike services that deliver to a single MX record, we needed to specify individual IP addresses for message delivery. We found existing services charging $500+ per month with limited flexibility. So we built our own solution. Since launching in 2018, MailFlowMonitoring has grown to serve over 10,000 businesses worldwide. We built the tool we wanted to use ourselves, with the alerting integrations modern teams need. Whether you're monitoring a single mail server or complex multi-server infrastructure, we have a plan that fits. **Our Mission:** Provide enterprise-grade email monitoring that's accessible to businesses of all sizes. Our Email Infrastructure Suite [ **AutoSPF** Automatic SPF record management under the 10 DNS lookup limit ](https://autospf.com)[ **DMARC Report** DMARC monitoring and reporting to protect your domain from spoofing ](https://dmarcreport.com)[ **Phish Protection** Advanced email security to block phishing and malware threats ](https://phishprotection.com)[ **Outbound SMTP** Reliable SMTP relay for transactional and marketing email ](https://outboundsmtp.com)[ **Tenant Migration** Seamless Microsoft 365 tenant-to-tenant migration services ](https://tenantmigration.com)[ **Inbox Issue** Email deliverability diagnostics and inbox placement testing ](https://inboxissue.com) FAQ ## Frequently Asked Questions What is round-trip email monitoring? Round-trip monitoring sends test emails to your mail server and tracks the auto-reply response. It validates that your MX records, SMTP server, spam filters, and full routing path are working correctly. If a response fails or exceeds your configured threshold, you get an alert immediately. Is MailFlowMonitoring really free? Yes. Your first monitor is completely free with no credit card required. Paid plans are available if you need to monitor additional servers or want shorter check intervals. How quickly will I be alerted to an issue? Alerts are sent as soon as a test fails or exceeds your configured timeout threshold. You can receive alerts via email, SMS, webhook, PagerDuty, or Slack, so your team is notified through whatever channel they already use. What email servers does it work with? MailFlowMonitoring works with any email server that can auto-respond to test messages, including Office 365, Google Workspace, Exchange, Postfix, Sendmail, and any other SMTP server. It is completely mail server agnostic. How long does setup take? Most users are up and running in under 10 minutes. You create an account, configure a test email address on your server that auto-responds, and enter the address into your dashboard. No software to install and no agents to deploy. ## Start monitoring your email infrastructure Join thousands of businesses ensuring their email reliability. Setup takes less than 10 minutes. [Create Your Account→](http://app.mailflowmonitoring.com/users/sign%5Fup) ```json {"@context":"https://schema.org","@type":"Organization","name":"MailFlow Monitoring","url":"https://mailflowmonitoring.com","logo":{"@type":"ImageObject","url":"https://mailflowmonitoring.com/images/mailflowmonitoring-logo.png"},"description":"Round-trip SMTP and IMAP email infrastructure monitoring service. 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