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DomainsDoc vs MXToolbox
MXToolbox has been the go-to free lookup site for ops people for two decades, and it earned that reputation. If you need to debug one DNS record or one SMTP handshake right now, it is excellent. DomainsDoc solves a different problem: instead of dozens of separate tools you run by hand, it bundles the checks that matter into one continuously-monitored health grade and alerts you when anything changes. Both are good tools. Here's where each one wins.
| Feature | DomainsDoc | MXToolbox |
|---|---|---|
| Bundled health grade | Single A–F grade across email auth, blacklists, SSL, expiry, and uptime | Domain Health report lists problems and warnings, no single grade |
| Continuous monitoring + alerting | Every 6h / 1h / 15min depending on plan, alerts on any change | Monitors on paid plans; limited free blacklist monitoring |
| Free instant check, no signup | Full health report with grade | SuperTool: one of the largest free lookup collections anywhere |
| DMARC aggregate-report analytics | We check your DMARC record and policy, but do not ingest RUA reports | DMARC report processing in Delivery Center |
| Blacklist monitoring | Checked against major DNSBLs on every run | A core strength, checks a very large list of blacklists |
| SSL, uptime, and domain-expiry monitoring | Included in every report on every plan | Available as separate paid monitors |
| MTA-STS, TLS-RPT, BIMI, DNSSEC checks | Part of the bundled report | One-off lookup tools exist; continuous coverage varies by plan |
| Slack / Discord alerts | On Pro and Agency | Alerting is primarily email-based |
| PDF reports | On Pro and Agency | Not a headline feature; check current plans |
| Price | Free check; monitoring from $9/mo | Free tools; paid monitoring suites run roughly $100+/mo |
Competitor details reflect our understanding as of June 2026 and may change. Always confirm on MXToolbox's own site before buying.
When MXToolbox is the better choice
- You need the toolbox. MXToolbox's SuperTool covers hundreds of one-off lookups, obscure DNS record types, header analysis, SMTP transaction tests, and more. DomainsDoc deliberately covers fewer checks. If you regularly need that breadth, MXToolbox is unmatched.
- You're diagnosing live SMTP problems. Their SMTP diagnostics (banner checks, open-relay tests, transaction-level testing) are genuinely useful for debugging a mail server in real time. DomainsDoc doesn't do interactive SMTP debugging.
- You want DMARC report analytics and monitoring from one large vendor. Their Delivery Center processes DMARC aggregate reports alongside blacklist and DNS monitoring, and bigger teams may prefer one established vendor for all of it.
When DomainsDoc is the better choice
- You want one grade, not thirty lookups. DomainsDoc runs SPF, DKIM, DMARC, MX, blacklists, SSL, domain expiry, uptime, and more in a single pass and rolls them into one A–F grade. No tool-hopping, no tabs.
- You want monitoring without enterprise pricing. Continuous monitoring with alerts starts at $9/mo for 5 domains. MXToolbox's monitoring suites are priced for larger teams.
- You want alerts where your team lives. Slack and Discord alerts (plus email) the moment a record changes, a blacklist hit appears, or a certificate is about to expire.
See your domain's grade in 30 seconds
Free, instant, no signup. Then decide if continuous monitoring is worth $9/mo to you.
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