The Pre-Q4 Email Deliverability Audit: What to Fix Before October

If you are running email for eCommerce clients, August is your last clean window before Q4. Deliverability problems take 3 to 6 weeks to fix. A problem found in October cannot be resolved before BFCM. This is the audit to run now.

This post is the agency-facing checklist: five audit areas, what to check for each client, what bad looks like, fix timelines, and a priority order for when everything needs work at once. For the full context behind each area, the eCommerce email deliverability guide is the reference.

Why August Is the Deadline

The eCommerce calendar creates a compounding chain. Amazon Prime Day (mid-July) drives an industry-wide volume spike. Brands that expanded to their full list generate reputation damage that takes 3 to 6 weeks to recover from — placing that recovery squarely in back-to-school season. A brand still recovering from Prime Day sends into back-to-school with weakened signals. By October, BFCM preparation needs to begin, but the damage is already stacked.

An audit completed in August gives you time to:

• Fix authentication issues before they affect Q4 sends
• Run 4 to 6 weeks of clean-sending recovery if list hygiene is degraded
• Warm up volume gradually rather than jumping straight to full-list BFCM sends
• Present findings to clients while there is still runway to act

The BFCM email deliverability guide covers the 8-week preparation timeline from September onward. This audit is what happens before that timeline starts.

The 5-Area Pre-Q4 Audit

1. Authentication

Severity if broken: Critical — non-compliant with Gmail and Yahoo bulk sender requirements, affects every send.

What to check:

• DMARC policy — is it at p=quarantine or p=reject? p=none means it is set up but not enforced.
• DKIM pass rate in Google Postmaster Tools — should be 100%. Anything below means a sending source is misconfigured.
• SPF record — does it include all current sending sources? Is it below the 10 DNS lookup limit?
• Sending subdomain — is the client on a branded subdomain (email.brand.com) or sending from the root domain?

What bad looks like:

• Most common: DMARC at p=none — found in the majority of eCommerce audits. Technically configured, not enforced. Non-compliant with Gmail and Yahoo bulk sender requirements since early 2024.
• DKIM pass rate at 95 to 98% — a new sending source (helpdesk tool, CRM notifications) was added without updating DNS.
• SPF with 9+ lookups — one more sending source will push it over the 10-lookup limit and break authentication on every send from that source.

Fix this first. DNS changes propagate in 1 to 3 days and authentication fixes unblock everything else. There is no reason any client goes into Q4 with p=none.

The SPF, DKIM, and DMARC guide covers the correct configuration for Klaviyo senders specifically.

2. Sender Reputation

Severity if broken: Critical — a damaged spam rate or active blacklist listing takes 3 to 6 weeks to recover and cannot be rushed.

What to check:

• Google Postmaster Tools v2 Compliance Dashboard — are all three signals passing (authentication, spam rate, bulk sending practices)?
• Spam rate trend — is it stable below 0.08%, rising, or already above 0.10%?
• Yahoo Sender Hub — Yahoo moves before Gmail. A declining Yahoo inbox rate is the earliest visible warning of a list quality problem.
• Blacklist status — run the sending subdomain and IP through Spamhaus DBL, Spamhaus SBL, and Barracuda.

What bad looks like:

• Most common: spam rate trending upward over 4 to 6 weeks — not yet at the 0.10% threshold but moving in the wrong direction. This will spike during BFCM volume increases if not addressed now.
• Yahoo inbox rate declining while Gmail holds steady — Gmail will follow in 4 to 8 weeks if unaddressed.
• A Spamhaus DBL listing the client does not know about.

Act immediately if the spam rate is rising or a blacklist is active. A rising spam rate takes 3 to 6 weeks of clean sending to recover. A blacklist listing clears in 1 to 2 weeks after root cause is fixed. If either is present, start remediation before finishing the rest of this audit.

The Google Postmaster Tools guide covers the current v2 interface and what each compliance signal means.

3. List Hygiene

Severity if broken: Critical — sending to unengaged subscribers is the root cause of most spam rate problems. The reputation damage compounds over time and peaks during BFCM volume increases.

What to check:

• Engagement segmentation — is the client excluding non-openers beyond 90 days from campaigns? Beyond 180 days for lower-frequency senders?
• Suppression list integrity — has it been accidentally overwritten by a CRM import or list upload in the last 3 months?
• Hard bounce rate per campaign — should be below 0.3%. Above 1% means a list source problem.
• Email validation at collection points — running at checkout, popups, and landing pages?

What bad looks like:

• Most common: sending to the full list including 12+ months of non-openers. This is the single biggest driver of BFCM complaint rate spikes. The list looks large; the engaged portion is a fraction of it.
• Suppression list overwritten during a platform migration — previously suppressed complainers are now receiving mail again.
• Hard bounce rate climbing above 0.5% — old segments or imported lists are being mailed.

Implement engagement segmentation first. It takes 1 to 2 days to build in Klaviyo. The reputation improvement takes 3 to 4 weeks of clean sending to show in Postmaster Tools — which is exactly why this needs to start in August.

The email list hygiene guide covers the Klaviyo segment builds for engagement-based suppression.

4. Inbox Placement Baseline

Severity if missing: High — without a placement baseline the client is making Q4 decisions based on delivery rate alone. Your ESP’s delivery rate does not show inbox vs. Promotions vs. spam.

What to check:

• Run a seed list test on the client’s last 3 campaigns — get the actual Gmail, Yahoo, and Outlook inbox vs. Promotions vs. spam split.
• Compare campaign placement vs. flow placement — welcome series and abandoned cart flows often show worse placement than campaigns because their audience drifts over time.
• Check for provider-level gaps — a blended 87% average can hide a 74% Yahoo rate masked by a 95% Gmail rate.

What bad looks like:

• Most common: no placement baseline exists. The client knows their delivery rate is 99% and assumes everything is fine. They have no idea where emails are actually landing.
• Gmail placement healthy, Yahoo consistently below 80% — list quality problem in progress. Gmail will follow in 4 to 8 weeks.
• Abandoned cart flow placing 15 to 20 points lower than campaigns — the flow’s audience has drifted and nobody has reviewed it.

Get the baseline today — it takes one test send. If placement is below 80% at any provider, treat it as a list hygiene problem (Section 3) and start fixes immediately. Do not wait for the full audit to be complete.

5. Sending Infrastructure

Severity if broken: Medium — infrastructure problems are slower to surface but harder to fix during peak. Do not leave them for October.

What to check:

• Dedicated vs. shared IP — if dedicated, is the client maintaining consistent monthly volume to sustain the IP’s reputation?
• Sending subdomain — is it consistent across campaigns and flows, or are multiple subdomains fragmenting the reputation?
• Send volume trend — stable month-over-month, or are there unexplained spikes?
• Klaviyo smart sending — enabled on all flows? The 16-hour default window prevents frequency stacking that drives complaint spikes.

What bad looks like:

• Most common: smart sending disabled on one or more flows. Subscribers triggering the abandoned cart flow multiple times per week receive several emails in a few days and mark one as spam. A single disabled toggle is often the source of a complaint rate problem that looks like a list issue.
• Dedicated IP with volume down 50%+ from warm-up levels — the IP’s reputation degrades without consistent sending to sustain it.
• Three different subdomains across campaigns, flows, and transactional sends — reputation is fragmented and impossible to meaningfully monitor.

Fix smart sending today — it takes 5 minutes per flow. Subdomain consolidation can be done in days. Do not make IP strategy changes in October — any infrastructure change that close to BFCM requires a warm-up period there is no time for.

Running This Across Multiple Clients

Not every client needs the same depth of work. Use this priority order to allocate your August hours.

Triage in 20 minutes. Request a Postmaster Tools screenshot and run a DNS lookup on every client simultaneously. This separates clients who need emergency remediation from clients who need maintenance before you spend a single hour on deep audit work.

Prioritize by revenue at risk. A client sending 500,000 emails per month with a rising spam rate has more exposure than a client sending 50,000 with clean signals. Do not give equal time to unequal risk.

Deliver a one-page findings report per client. Each finding gets a severity label (Critical / Needs Attention / Healthy), one sentence of business impact, and a remediation step with a timeline. Clients who receive this in August act on it. Clients who receive a deliverability problem report in November do not have time to.

Pre-Q4 Audit Checklist

Save this and run it for each client by end of August.

Authentication

• DMARC policy at p=quarantine or p=reject
• DKIM pass rate at 100% in Postmaster Tools
• SPF record covers all sending sources and is below 10 DNS lookups
• Client is sending from a branded subdomain, not root domain

Sender Reputation

• Postmaster Tools v2 compliance signals all passing
• Spam rate below 0.08% and stable or declining over past 30 days
• No active blacklist listings on Spamhaus DBL, SBL, or Barracuda
• Yahoo inbox rate stable or improving (check Sender Hub or seed list data)

List Hygiene

• Non-openers beyond 90 days excluded from campaigns
• Suppression list intact — no recent overwrites from imports or migrations
• Hard bounce rate below 0.3% per campaign
• Email validation running at all collection points

Inbox Placement

• Seed list test run on at least 3 recent campaigns
• Gmail, Yahoo, and Outlook placement documented as a baseline
• Welcome series and abandoned cart flow placement checked separately
• No provider-level gap above 15 percentage points

Infrastructure

• Sending subdomain consistent across all sends
• Smart sending enabled on all flows (16-hour default window confirmed)
• Send volume stable month-over-month — no unexplained spikes
• Dedicated IP clients: volume maintained above warm-up threshold

Where to Start

If you have not run a placement baseline for a client, do that first. One seed list test tells you more than an hour of dashboard review. Everything else — authentication, list hygiene, infrastructure — feeds into where the placement problem is coming from.

If the audit surfaces a crisis-level finding (active blacklist, spam rate above 0.10%, Postmaster compliance signals failing), start the email deliverability crisis recovery process immediately. Do not wait until September.

Once Q4 is over, the agency email deliverability checklist covers the monthly cadence for keeping clients clean year-round so you are not running emergency audits every August.

Note: Content created with the help of AI and human-edited and fact-checked to avoid AI hallucinations.