Email deliverability monitoring for agencies
For freelancers and agencies watching many client sites, email deliverability is the problem you get blamed for but can't see. When a client's form notifications or newsletters start hitting spam, the call comes to you — and the cause is almost always three DNS records: SPF, DKIM and DMARC. Here's what they do and how to keep them working.
SPF — who's allowed to send
SPF is a DNS TXT record listing which servers may send mail for the domain. Without it, anyone can spoof the domain and receiving servers have no way to tell legitimate mail from forgeries — so more of it lands in spam. The record should end in ~all (soft fail) or -all (hard fail); a +all is a wide-open door.
DKIM — a tamper-proof signature
DKIM adds a cryptographic signature to each message that the receiving server verifies against a public key in DNS. It proves the mail wasn't altered in transit. DKIM uses a per-domain selector, so it can't be verified from DNS alone without knowing that selector — check it in your mail provider's dashboard.
DMARC — the enforcement policy
DMARC ties SPF and DKIM together and tells receivers what to do when mail fails: p=none (monitor only), p=quarantine (spam folder) or p=reject (block). Many domains stop at p=none and never enforce, leaving the spoofing door open. Move toward quarantine, then reject.
Monitor it, don't set-and-forget
These records drift — a new mail tool needs adding to SPF, a migration drops DMARC. Check any domain now with our free email deliverability checker, and monitor it across a whole client portfolio so a deliverability regression becomes an alert, not a lost-leads mystery.
Frequently asked questions
Why do client emails suddenly go to spam?
Usually a missing or weak SPF/DMARC record, a mail tool that isn't in SPF, or a DMARC policy left at p=none. Fixing SPF and DMARC resolves most cases.
Can you check DKIM automatically?
Not from DNS alone — DKIM needs the domain's specific selector. We check the selector-free signals (SPF, DMARC, MX) and flag that DKIM needs a manual check in your mail provider.
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