Alternatives to MXToolbox
A web-based suite of DNS, MX, SPF, DMARC and blacklist lookups for diagnosing email delivery. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
MXToolbox
A web-based suite of DNS, MX, SPF, DMARC and blacklist lookups for diagnosing email delivery.
Replacements
Listings that take over the same core job as MXToolbox.
GlockApps
An online email deliverability tester that checks inbox placement, spam scores, blocklists and domain authentication.
GlockApps adds inbox placement testing across major mail providers to SPF, DKIM, DMARC and blocklist checks, with full seed-list tests on paid plans.
Internet.nl
A web test that checks websites, mail domains and connections for modern Internet standards support.
Internet.nl tests mail domains for DMARC, DANE, DNSSEC and TLS in one combined report, is free and can run self-hosted through Docker.
intoDNS
A free web tool that checks a domain's DNS and mail server health and configuration.
intoDNS gives a single free report on DNS and mail server health with fix suggestions, but lacks blacklist checks and separate SPF or DMARC tools.
Maileroo Mail Tester
A free web tool that grades a test email for authentication, spam score, DNS and blacklists.
Maileroo Mail Tester grades a real delivered message for SPF, DKIM, blacklists, BIMI and MTA-STS instead of running separate lookups per record.
DNSsy
A free website that tests a domain's DNS health and offers live DNS, reverse, WHOIS and ping lookups.
DNSsy offers a free DNS health report with basic mail server checks and live lookups, but has a smaller set of tools than MXToolbox.
ViewDNS.info
A web collection of more than 20 DNS, IP and domain lookup tools, with a paid API.
ViewDNS.info collects more than 20 DNS, IP and domain lookups with historical data, but focuses less on email and has a paid API.
Also worth comparing
These listings name MXToolbox as their own alternative, so the relationship runs both ways.
dmarcian DMARC Inspector
A free web tool that shows a domain's DMARC record and checks it for syntax and policy issues.
MXToolbox validates DMARC with error highlighting alongside SPF, MX and blacklist checks in one suite, with pages carrying prompts for its paid service.
DNSChecker
A web tool that checks DNS propagation by querying public resolvers in many countries.
MXToolbox runs many DNS and email lookups, querying authoritative servers directly, with prompts for its paid service instead of global resolver comparisons.
EasyDMARC DKIM Lookup
A free web tool that looks up and validates a domain's DKIM record for a given selector.
MXToolbox bundles DKIM with MX, SPF, DMARC and blacklist lookups in one freemium suite, with each check run separately and prompts for its paid service.
EasyDMARC DMARC Lookup
A free web tool that looks up a domain's DMARC record and checks it for configuration errors.
MXToolbox validates DMARC with error highlighting within a larger suite of DNS, MX, SPF and blacklist lookups, each run separately, with prompts for its paid service.
Google Admin Toolbox Dig
Google's free web-based DNS lookup tool that queries a domain's records and shows the results.
MXToolbox queries the authoritative server directly for MX lookups and adds SPF, DMARC and blacklist checks, with prompts for its paid service on the pages.
Kitterman SPF Validator
Online SPF tools that retrieve and validate a domain's SPF record or test a draft record.
MXToolbox validates SPF with error highlighting alongside DMARC, MX and blacklist checks, but its pages carry prompts for the paid service.
Mimecast DMARC Checker
A free web tool that fetches a domain's DMARC record and explains each tag and policy.
MXToolbox validates DMARC with error highlighting and also covers SPF, MX and blacklist checks as separate lookups on one site.
MultiRBL
A free tool that checks a mail server IP against over 200 DNS blacklists and whitelists.
MXToolbox pairs a 105-list blacklist check with MX, SPF and DMARC lookups in one freemium suite, with prompts for its paid service.
MXToolbox Blacklist Check
An online tool that tests a mail server IP or domain against over 100 DNS blacklists.
MXToolbox's full suite adds MX, SPF and DMARC lookups to the blacklist check, with freemium pricing and prompts for the paid service.
MXToolbox DKIM Lookup
A free web tool that tests whether a domain publishes a valid DKIM public key for a selector.
MXToolbox's wider suite runs the same DKIM check alongside MX, SPF, DMARC and blacklist lookups, with prompts for its paid service.
Similar software
Related functionality, not a direct replacement.
LearnDMARC
An interactive web console that visualizes how SPF, DKIM and DMARC evaluate a real email.
