Free deliverability tools
Audit your domain in seconds. Run real DNS lookups on SPF, DKIM, DMARC, MX, blacklists and verify email addresses — no signup required.
Validate Sender Policy Framework records.
Open toolCheck DKIM signing keys on any selector.
Open toolInspect DMARC policy, alignment, reporting.
Open toolSee mail servers and identify the provider.
Open toolScan an IP or domain across 10+ DNSBLs.
Open toolSyntax, MX, disposable + role detection.
Open toolComposite 0–100 deliverability score for any domain.
Open toolScore your subject and body for spam-filter risk.
Open tool20+ proven cold email subject lines, instantly.
Open toolDeliverability-safe HTML email signature in seconds.
Open toolWhy domain checks come before your first campaign
Most cold email problems are infrastructure problems wearing a copywriting costume. Before you rewrite a subject line, confirm the boring things: the domain resolves, SPF lists every sender you actually use, DKIM is published and signing, DMARC exists with a reporting address, and the domain is not sitting on a public blacklist. Each tool here runs a live DNS lookup so you see the record as receivers see it, not as your provider's dashboard claims it is.
A five-minute pre-launch routine
- Check SPF and confirm there is one record with fewer than ten lookups.
- Check DKIM on the selector your provider gave you and verify the key is present.
- Check DMARC and make sure reports are being sent to a mailbox someone reads.
- Check MX so replies and bounce notifications actually reach you.
- Check blacklists and domain reputation before you add volume, not after.
- Verify a sample of your list so bounces never cross two percent.
What these tools cannot tell you
DNS records prove your setup is technically correct. They cannot tell you whether a mailbox is warmed, how much volume a domain can carry this week, or whether recipients are marking your mail as spam. Those depend on sending behaviour over time: ramp slowly, keep volume steady per mailbox, spread sending across domains, and watch reply rates rather than open rates.
When to fix versus when to start clean
A misconfigured record is worth fixing. A domain with a damaged reputation usually is not — reputation recovery takes longer than starting fresh on a new sending domain with correct authentication from the first message. If checks come back clean but placement stays poor, the domain history is likely the issue.