MXToolbox Review 2026: SuperTool, Blacklist Check & Pricing

MXToolbox is the email diagnostics suite most administrators reach for first when something is wrong with mail. Need to know whether your sending IP is on a blacklist, whether your MX records resolve, or whether your SPF and DMARC are valid? MXToolbox answers all of that in seconds, for free. This MXToolbox review explains what the tool does, the famous free SuperTool, the paid Delivery Center, MXToolbox pricing in 2026, and where it fits among email testing tools. It is part of our email verification and testing hub.

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What is MXToolbox?

MXToolbox is a long-established suite of DNS, email and blacklist diagnostic tools, used by IT teams, sysadmins and deliverability specialists to look up and monitor the health of mail servers and domains. Its on-demand lookups are free and unlimited: you can check a domain’s mail-exchange (MX) records, test whether an IP is listed on more than a hundred blocklists at once, validate SPF, DKIM and DMARC, run an SMTP connectivity test, and perform general DNS lookups. On top of those free checks, MXToolbox sells continuous monitoring and a deliverability product called Delivery Center. The defining quality of MXToolbox is that it is a diagnostics tool — it tells you whether your infrastructure and reputation are healthy, which is the first question to answer whenever mail is not being delivered.

The MXToolbox SuperTool and its free checks

The heart of MXToolbox is the SuperTool: a single search box that runs any of its diagnostics depending on a command prefix you type. Enter mx: a domain for its mail servers, blacklist: an IP to test it against the major real-time blocklists, spf: or dmarc: to validate authentication, or smtp: to test a mail server’s connectivity and check for an open relay. The same box also handles A, TXT, CNAME, PTR and DNSSEC lookups, WHOIS, ping, traceroute and a header analyzer. Consolidating thirty-plus separate tests behind one box is what made MXToolbox the default bookmark for email troubleshooting, and all of those on-demand lookups remain free and unlimited.

The MXToolbox blacklist check deserves special mention because it is the tool most people know by name. Paste a sending IP or hostname and it queries more than a hundred DNS-based blocklists (DNSBLs) simultaneously, returning a clear listed-or-clean result for each. When deliverability suddenly drops, an email blacklist check is the fastest way to rule in or out a listing as the cause — and if you are listed, MXToolbox links you to each blocklist’s delisting process. For the background on which lists matter and how to get removed, see our email blacklist guide.

MXToolbox pricing in 2026

MXToolbox pricing separates the free on-demand tools from paid monitoring and the Delivery Center deliverability product. The official, clearly published tiers are below; some intermediate monitoring plans quoted by third parties are not confirmed on the current pricing page, so treat anything outside this table as indicative only.

The practical takeaway on MXToolbox pricing is that the free tier is generous for diagnostics but thin for monitoring — you get a single weekly monitor, which checks a limited set of blacklists once a week. Teams that need continuous, multi-list monitoring with faster alerting move up to a paid monitoring plan, and those that want full deliverability reporting, inbox-placement data and feedback-loop processing buy Delivery Center. Because the lower-cost monitoring tiers are not consistently documented on the official site, confirm what you need directly on the official MXToolbox products page before committing.

MXToolbox features at a glance

• SuperTool — one search box for MX, blacklist, SPF, DKIM, DMARC, SMTP and DNS lookups.
• Blacklist check — tests an IP or host against 100+ DNSBLs at once with delisting links.
• Authentication validation — SPF, DKIM and DMARC record lookups and syntax checks.
• SMTP diagnostics — connection test, banner check, open-relay and reverse-DNS checks.
• Monitoring — scheduled re-checks with email alerts (1 free; more on paid plans).
• Delivery Center — inbox placement, complaint/feedback-loop reporting and mailflow monitoring for senders.

MXToolbox pros and cons

• Pro — the industry-default free diagnostics: unlimited MX, blacklist, SPF/DKIM/DMARC and SMTP lookups.
• Pro — the SuperTool consolidates thirty-plus separate tests behind one fast search box.
• Pro — trusted and mature, with broad blocklist coverage and clear Delivery Center pricing.
• Con — free monitoring is thin (a single weekly blacklist monitor).
• Con — diagnostics-first, not a fix-it platform: it surfaces problems but does not guide DMARC deployment or warm-up.
• Con — mid-tier monitoring pricing is opaque, and the interface is utilitarian.

Who MXToolbox is best for

MXToolbox is best for IT administrators, sysadmins, managed-service providers and deliverability teams who need fast, reliable on-demand diagnostics — and for organisations that want continuous blacklist and mailflow monitoring with proper reporting. If your day involves answering “is this IP blacklisted?” or “are these DNS records valid?”, the free SuperTool is indispensable and you may never need to pay. It is a weaker fit if what you actually want is to improve deliverability through guided DMARC enforcement or inbox warm-up, because MXToolbox diagnoses rather than remediates — for that, a dedicated DMARC platform or a placement-testing tool like GlockApps is the better companion. Diagnostics and improvement are different jobs, and most serious senders use a tool for each.

How MXToolbox fits a deliverability workflow

Think of MXToolbox as the diagnostic first responder. When mail stops flowing or placement drops, you start with an email blacklist check on your sending IP, confirm your MX records resolve, and validate that SPF, DKIM and DMARC are present and syntactically correct. Those checks rule the most common infrastructure failures in or out within minutes, which is why MXToolbox is the tool people open before anything else. Once you have established that the infrastructure is sound, you move to the harder question of actual inbox placement, which a seed-list tester answers and MXToolbox does not (outside the Delivery Center add-on).

For ongoing operations, the monitoring layer turns those one-off checks into an early-warning system: schedule a blacklist monitor so you are alerted the moment a sending IP gets listed, rather than discovering it days later when open rates crater. Combined with disciplined list hygiene through verification and a healthy sender reputation, MXToolbox monitoring closes the loop between “something broke” and “we knew immediately.” It will not fix the underlying problem for you, but it will make sure you find out about it fast.

MXToolbox vs the alternatives

The key distinction is that MXToolbox checks infrastructure health, whereas placement testers check where mail lands. MXToolbox tells you that your records are valid and your IP is not blacklisted; it does not send to seed inboxes and report inbox-versus-spam placement across providers — that is the job of GlockApps or a quick free score from Mail-Tester. Most senders use both kinds of tool: MXToolbox as the everyday diagnostic and a placement tester for inbox confidence before a major send.

For authentication specifically, MXToolbox validates your SPF, DKIM and DMARC records but does not manage a DMARC rollout the way dedicated platforms such as dmarcian, EasyDMARC or PowerDMARC do — those parse aggregate reports at scale and guide you from p=none to enforcement. If your goal is to deploy and tighten DMARC across many domains, pair MXToolbox’s quick checks with one of those, or follow our own DMARC record guide. See where MXToolbox sits among the full set of testing tools in our best email testing and verification tools roundup.

The verdict on MXToolbox

MXToolbox is the default free diagnostic toolkit for email, and that reputation is well earned. The SuperTool’s consolidation of MX, blacklist, authentication and SMTP checks behind one search box is genuinely useful every single working day, the blacklist check is the fastest way to diagnose a sudden deliverability drop, and the on-demand lookups cost nothing and have no usage cap. For most administrators it is an essential bookmark and frequently all they need.

The caveats are about scope rather than quality. MXToolbox is a diagnostics-and-monitoring product, not a deliverability-improvement platform: it shows you that something is wrong but leaves the remediation — DMARC enforcement, warm-up, reputation repair — to you and other tools. Free monitoring is limited to a single weekly monitor, and the mid-tier monitoring pricing is not transparently published, though the Delivery Center tiers are. Take it for what it is, and it is excellent. Use MXToolbox as your everyday diagnostic, layer monitoring on top for early warnings, and pair it with a placement tester and a DMARC platform for the parts it deliberately does not cover. Compare it with the rest of the field in our email verification and testing hub.

Make your emails actually land

Whichever tool you use to send or verify, deliverability is what decides whether your email reaches the inbox — make sure these foundations are in place:

• Free Email Health Check — score your sending domain out of 100 in 30 seconds — the fastest way to see what to fix.
• Email deliverability hub — reputation, warm-up, blacklists and inbox placement.
• Gmail, Yahoo & Microsoft sender requirements — the rules bulk senders must now meet to be delivered.
• Email authentication (SPF, DKIM & DMARC) — prove your mail is really yours and stop spoofing.

Related reading

• ZeroBounce review
• NeverBounce review
• Best email verification tools
• GlockApps review
• Best deliverability tools

MXToolbox review: FAQ

Is MXToolbox free?

Yes — MXToolbox’s on-demand lookups (MX, blacklist, SPF, DKIM, DMARC, SMTP and DNS checks via the SuperTool) are free and unlimited, plus one free weekly blacklist monitor. Continuous multi-list monitoring and the Delivery Center deliverability product are paid. For most diagnostic needs you never have to pay.

How does the MXToolbox blacklist check work?

You enter a sending IP or hostname and MXToolbox queries more than a hundred DNS-based blocklists at once, returning a listed-or-clean result for each. If you are listed, it links to each blocklist’s delisting process. An email blacklist check is the quickest way to confirm whether a listing is causing a deliverability problem.

What is the MXToolbox SuperTool?

The SuperTool is a single search box that runs any MXToolbox diagnostic based on a command prefix — for example mx:, blacklist:, spf:, dmarc: or smtp: followed by a domain or IP. It consolidates more than thirty separate tests into one interface, which is why it is the most-used part of the product.

How much does MXToolbox cost?

The free tier covers unlimited on-demand lookups plus one weekly monitor. Paid plans include Delivery Center at about $129/mo (inbox placement, complaint reporting, monitoring for 5 domains / 500k messages) and Delivery Center Plus at about $399/mo. Some intermediate monitoring tiers are quoted by third parties but not consistently published officially.

Does MXToolbox test inbox placement?

Only on the paid Delivery Center plan, which adds inbox-placement analysis. The free MXToolbox tools check infrastructure — records, blacklists, SMTP — not where your mail lands. For seed-list placement testing on a budget, pair MXToolbox with a tool like GlockApps or a free score from Mail-Tester.

Is MXToolbox worth it?

The free MXToolbox tools are worth it for virtually every sender and administrator — they are the fastest way to diagnose DNS, authentication and blacklist problems. Whether the paid plans are worth it depends on whether you need continuous monitoring and deliverability reporting; many teams happily use only the free SuperTool.