A free MXToolbox alternative for everyday checks
MXToolbox is the pro's Swiss-army knife for DNS and email diagnostics. Cactus covers the everyday checks - email auth, TLS, blacklists, certs - explained simply and free.
What MXToolbox is good at
MXToolbox is the professional's Swiss-army knife for DNS, email, and network diagnostics. It runs an enormous range of lookups - MX records, blacklists, DNS, SMTP diagnostics, and much more - and offers monitoring and paid plans for teams. If you administer mail servers or domains for a living, it's hard to beat the depth.
What Cactus does
Cactus focuses on the checks most people and small businesses actually need, and explains the results in plain language - free, no signup, and bilingual:
- Email authentication - SPF, DKIM, DMARC, plus DNSSEC, CAA and MTA-STS, with an A-to-F grade.
- SSL/TLS - certificate, protocol, cipher and chain, graded A+ to F.
- IP reputation - who owns an IP and whether it's on spam/abuse blacklists.
- Certificate search - a domain's subdomains and issued certificates from public CT logs.
How they compare
| MXToolbox | Cactus | |
|---|---|---|
| Breadth of lookups | Very large | The common ones, focused |
| SPF/DKIM/DMARC grade | Yes | Yes (plus DNSSEC/CAA/MTA-STS) |
| SSL/TLS grade | Yes | Yes |
| Blacklist / IP reputation | Yes | Yes |
| Monitoring / paid tiers | Yes | No - all free |
| Plain-language results | Technical | Beginner-friendly |
| Bilingual (EN/FR) | No | Yes |
Which should you use?
If you're a mail administrator who needs every lookup type and ongoing monitoring, MXToolbox is the deeper tool. If you want the everyday email, TLS, blacklist and certificate checks explained clearly - for free, in English or French - Cactus is the simpler choice.