An email deliverability audit that finds why you land in spam, and fixes it.

The global average inbox-placement rate in 2026 sits around 83.5%, which means close to a sixth of permission-based mail lands in spam or vanishes rather than reaching the primary inbox. European inboxes do better, near 91%, and the figure varies by industry from the mid-eighties to the low nineties, but the principle holds everywhere: a message that the mail server accepted is not a message a person saw. A campaign can report healthy delivery and still be missing most of its audience, because delivered counts mail that reached the spam folder, and inbox placement counts only what reached the inbox.

For a sender of any scale the gap is measured in pipeline rather than in bounce reports. The difference between 86% and 92% placement on a list of a million, sending weekly, is millions of additional messages seen across a year. Open rates above 90% placement are considered healthy, above 95% excellent, and anything below 80% points to a problem that needs immediate attention. When open rates collapse without anything else changing, the cause is almost always a deliverability problem that has been building quietly, and an audit is how you find it before the next campaign goes out half-blind.

For years the advice was simple: set up SPF, DKIM and DMARC, and your mail reaches the inbox. In 2026 that advice is misleading. Analysis across large mail corpora in 2025 found that fully authenticated mail still landed in spam more than 30% of the time, because mailbox providers now weigh how real people engage with your messages, the opens, clicks, replies and complaints, far more heavily than a passing authentication check. Authentication is the condition for being considered at all; it is not what wins the inbox.

This is where most audits stop short. They confirm the records are present and call the job done, when industry data consistently traces around 80% of deliverability failures back to list quality: invalid addresses, disposable signups, role accounts and dormant contacts that pile up over time and quietly poison engagement. A deliverability audit that matters goes past the authentication layer into the list and the sending behaviour, because that is where the failures that survive a clean DNS check genuinely live. We treat authentication as the first checkbox rather than the conclusion.

# SPF — must resolve to exactly ONE record, ending in -all or ~all
$ dig +short TXT example.com | grep spf1
"v=spf1 include:_spf.example.com -all"

# DMARC — policy at the _dmarc subdomain; p=reject is enforcement
$ dig +short TXT _dmarc.example.com
"v=DMARC1; p=reject; rua=mailto:[email protected]; adkim=s; aspf=s"

# DKIM — public key at the selector named in the signature
$ dig +short TXT s1._domainkey.example.com
"v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQ..."

# Live test send — read the Authentication-Results the receiver writes
$ swaks --to [email protected] --from [email protected] \
        --server mail.example.com --tls
Authentication-Results: mx.google.com;
   spf=pass dkim=pass dmarc=pass (p=REJECT)

Those four checks are the authentication layer as a mailbox provider sees it, not as a dashboard claims it. The single most common failure they surface is two SPF records on one domain, left behind after a provider switch, which makes SPF fail outright; the second is DMARC stuck at p=none, which monitors but enforces nothing. We run these against your live domain at the start of every audit, because a record that looks right in a control panel can still resolve wrong in the wild.

Most senders do not lose the inbox in a single event. It erodes. A list accumulates dead addresses and old signups that no longer open, so the engagement signals the mailbox providers watch drift downward month by month. A provider switch leaves an orphaned SPF record behind, and now two exist where only one is allowed, which makes authentication fail silently for a slice of mail. A run of heavier sending nudges the complaint rate from comfortable toward the 0.1% mark where reputation starts to suffer, well before it reaches the 0.3% that triggers hard filtering at Gmail. None of these announces itself; they show up as open rates that slide a little each month until someone notices the campaign is not working.

By the time the symptom is obvious, the cause is usually several steps back. That is why an audit reads the chain in order rather than reacting to the last thing that changed: the visible drop in opens is often the end of a sequence that began with a list or an authentication problem weeks earlier. Finding the first failure, rather than the most recent symptom, is what turns an audit into a fix instead of a guess.

Most deliverability audits are produced by a checklist tool or a consultant who hands over a PDF and leaves the fixing to you. Ours comes from people who run sending infrastructure every day, which changes both the diagnosis and what happens next. The diagnosis is sharper because we have seen these failures in production rather than read about them, and the remediation is real because the technical fixes, the authentication, the reverse DNS, the infrastructure and the warmup, are work we can carry out on our own email infrastructure or alongside your existing setup.

We are clear about the division, because deliverability is partly yours to own. The technical layer is ours to fix; the parts that depend on you, the consent behind your list, the relevance of your content and the cadence of your sending, are yours, and no audit can outsource them. Inbox placement is improved by removing failure points one at a time rather than guaranteed by a single change, and a damaged domain reputation recovers over weeks of clean sending rather than overnight. What we promise is an honest diagnosis and the technical work to act on it, not a number we cannot control. Where the answer is to rebuild the sending setup properly, that leads into our infrastructure work; where it is to resell sending under your own brand, it leads to our white-label email service.

Deliverability is the work we know best. We operate mail-transfer infrastructure, manage dedicated IP reputation and warm sending domains as a matter of routine, so an audit from us reflects what keeps mail landing in practice rather than a generic template. We have recovered domains from a bad reputation, fixed authentication that broke during a provider switch, and watched the engagement signals that decide placement move in real time. That experience is the difference between an audit that names the obvious and one that finds the cause a checklist would miss. We have also seen the false alarms: a third-party score flashing red while the providers' own signals say the mail is fine, which a tool would escalate and an operator recognises for what it is. The output is a clear picture of where your sending stands and a route to the inbox, written by people who would be comfortable fixing it themselves.