What an Email Deliverability Audit Covers (and What It Cannot Promise)

Short answer: A deliverability audit checks what mailbox providers can see and what the sender controls: authentication records, sending reputation, list quality, complaint and bounce signals, content and links, and whether marketing mail is kept apart from transactional mail. It shows what is likely hurting delivery and the order to fix it, but it cannot promise any specific inbox placement.

1. Authentication records

Start with SPF, DKIM, and DMARC on every domain that sends mail, including subdomains and any tool that sends on your behalf. For each record, the audit should confirm that it exists, sits on the right domain, and parses correctly. A domain with two SPF records fails the check outright, and a record that stacks many sending services can run into SPF's limit on DNS lookups.

DKIM is checked against the selectors your sending tools actually sign with, since a published key that no tool uses proves nothing. DMARC should exist and state a policy. A policy of none collects reports without asking receivers to act, so the auditor should say whether the domain is ready for a stricter policy and what evidence supports that, rather than recommending it by default. Gmail and Yahoo also expect bulk senders to authenticate their mail and publish a DMARC record.

For what each record does and how to set one up, read the SPF, DKIM, and DMARC setup guide. A dkim spf dmarc setup consultant should be able to walk through the same records line by line, with the actual values in front of you. If the auditor cannot show the record, selector, or DMARC report behind a finding, treat that finding as unconfirmed until they can.

2. Sending domain and reputation

Reputation attaches to the sending domain and, for dedicated infrastructure, to the sending IP. The audit should list every domain and subdomain that sends, check whether the visible From domain aligns with the domain that authenticates the message, and review sending history for sudden jumps in volume. A new domain that starts with a large send is a common source of trouble, and so is a domain that changes sending tools often.

Shared infrastructure adds a wrinkle. On a shared platform, part of the reputation tied to the sending IP depends on other senders using it, so the auditor should separate what you control, such as your domain and your list, from what the platform controls.

Monitoring tools show some of these signals over time. The email deliverability tools comparison looks at three specific monitoring tools and how they differ, which helps when you ask an auditor what will be monitored after the fixes.

3. List quality and complaint signals

Bounces, unknown addresses, and complaints are the signals most within the sender's control. The audit should pull them from the sending platform and look for trends across several sends, not one bad campaign. It should also ask where each address came from and when that contact last engaged. A large list of old, unengaged addresses tends to hurt more than a smaller, active one.

Complaints need their own check. The audit should show complaint signals per campaign and per segment, and confirm that marketing mail includes a working one-click unsubscribe.

Bounces need their own rule. Hard bounces should be suppressed immediately, so an audit that finds repeated sends to bounced addresses has found a process gap, not just a list problem.

List quality is also a compliance question. Check the rules that apply to your recipients, whether that is CAN-SPAM, GDPR, or India's Digital Personal Data Protection Act, 2023, and confirm sender identity, opt-out, consent, and lawful basis for each segment you mail.

4. Content, links, and tracking

Content is a smaller factor than authentication and list quality, but the audit should still review it. Look at link domains that do not match the sending domain, shortened URLs, image-heavy emails with little text, and click-tracking domains shared across many senders. Each can add noise to a reputation that is already weak.

A list of spam trigger words is a weak signal on its own. If you hire a consultant to fix email spam issues, the fix should follow the sending data, not a checklist of words.

5. Transactional and marketing separation

Receipts, password resets, and shipping notices are expected by customers and often matter more than promotions. Where possible, they should not share a sending stream or subdomain with bulk marketing. If a promotional campaign draws complaints, a shared stream can drag transactional mail down with it.

The audit should identify which system sends each type of mail, whether separate subdomains or streams are in use, and what would happen to order and account messages if promotional complaints rose. A transactional email setup consultant should also confirm that the authentication records cover every tool that sends transactional mail, not only the marketing platform.

6. What the report should contain

A useful report gives you three things. First, each finding with its evidence attached: the record checked, the log reviewed, or the report read. Second, a ranked fix list with one owner for each item. Third, a plain statement of limits: an audit can see your configuration and your sending data, but it cannot see every filtering decision a mailbox provider makes.

When you hire an email deliverability consultant or compare an email deliverability audit service, check that the proposal commits to all three parts. Many fixes live in DNS records and platform settings rather than in the report, so make sure whoever holds that access can act on it. For the wider email program an audit sits within, the email marketing page describes the email side of the work.

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