Check whether a sending domain has the DNS basics in place.

Look up the records cold email infrastructure depends on before you create inboxes, export accounts, or approve a launch gate.

How it works

  • The checker queries public DNS for MX, SPF, DMARC, and common DKIM selector records.
  • SPF records are parsed for duplicate policy records and the RFC 7208 10-lookup limit.
  • Results are returned in the page and through the public JSON endpoint for automation.

When to use it

  • Before provisioning inboxes on a new client domain.
  • After changing Cloudflare, registrar, or workspace DNS records.
  • Before exporting SMTP inboxes to a sequencer such as Smartlead or Instantly.

Common failure cases

  • Publishing two SPF TXT records instead of one combined policy.
  • Forgetting DMARC at `_dmarc.example.com` after SPF and DKIM are configured.
  • Checking DKIM before the selector used by the sending server is known.

Examples

What good and bad signals look like

Good signal

One SPF record, aligned DMARC, valid MX, and DKIM selector found

The domain has the baseline records expected before readiness checks continue.

Bad signal

Multiple SPF records or SPF lookup count over 10

Receivers may treat SPF as failed or permerror until DNS is cleaned up.

What to do next

  • Generate a corrected SPF or DMARC record if a policy is missing.
  • Re-check after DNS propagation before treating the domain as launch-ready.
  • Use the readiness report before prospect traffic; DNS alone is not placement proof.
Turn DNS checks into a workflow

Use the API quickstart to connect DNS checks, readiness reports, and export gates.

Related tools and workflows

SPF record generator

Build one combined SPF policy for your approved senders.

DMARC record generator

Create a monitoring or enforcement policy after SPF and DKIM align.

Domain capacity calculator

Estimate how many domains you need before DNS setup starts.

Cold email inbox calculator

Turn a DNS or authentication check into a conservative inbox-capacity plan.

FAQ

Is a passing DNS check enough to start cold email?

No. DNS is only one readiness input. SMTP, IMAP, launch gates, and seed-placement evidence still need to pass before prospect traffic.

Does GTM Inboxes store domains entered into this checker?

No. The public tool performs the lookup for the request and does not store submitted domains.