Guides
Cold email infrastructure guides
Every record and check that decides whether an outbound launch is Ready, Needs Fix, or Do Not Launch. What each one is, why it matters, and how to set it up.
SPF for cold email
The exactly-one-record rule, the 10 DNS lookup limit, and the SPF mistakes that block a launch.
DKIM for cold email
Selectors, public keys in DNS, and DKIM setup for Google Workspace and Microsoft 365.
DMARC for cold email
Policies, alignment, rua reports, and the Gmail and Yahoo requirement that made DMARC mandatory.
MX records and mail routing
How MX records route replies and bounces, provider records for Google and Microsoft, and common mistakes.
Domain warmup and safe sending volume
Why new domains are high risk, ramp schedules, per-inbox daily limits, and domain age.
Email blacklists: check and delist
The RBLs that matter, how listings happen, how to check before launch, and the delisting process.
Tracking domains: CNAME and SSL
Custom tracking domains, the CNAME to your sending tool, and why broken SSL kills click-through.
Google and Yahoo bulk sender requirements
SPF, DKIM, DMARC, one-click unsubscribe, and the spam-rate thresholds bulk senders must meet.
Run the matching checks
Use the guides to understand the setup, then verify the records with the same free tools linked from each guide.
Auth Checker
Run SPF, DKIM, and DMARC together for a sending domain before launch.
RBLBlacklist Checker
Check a domain and sampled mail server IPs against domain and email blocklists.
DELIVDeliverability Checker
Check observable cold email infrastructure readiness across MX, SPF, DKIM, DMARC, blacklist, age, tracking-domain, and SMTP egress identity signals.