Email Diagnostic Tools
Free tools for deliverability and infrastructure work. All checks run live — no log retention, no signup, rate-limited by IP. API access opens with the Starter plan (€19/mo).
Blacklist Checker →
Test any IP or domain against 30 DNS-based blocklists in parallel: Spamhaus, SpamCop, Barracuda, SORBS, UCEPROTECT and more.
SPF Checker →
Parse and validate any domain's SPF record. Counts DNS lookups against the RFC 7208 limit of 10 and flags weak policies.
DMARC Checker →
Check DMARC policy strength on any domain: p=, alignment mode, reporting addresses, percentage ramp.
MX Record Lookup →
Show all MX records for a domain with priority, IPv4/IPv6 resolution, and mail-provider identification (Microsoft 365, Google, etc.).
Email Verification →
Validate a single email address with five layers: syntax, MX, disposable, role-account, and live SMTP RCPT probing.