Last year, I got on a call with a publisher who was about to blow up his entire Black Friday campaign.
He'd been planning for months. Built out his sequences. Lined up his sponsors. Had 200K subscribers ready to go.
His plan? Go from sending 10K emails per day in October to 500K on Black Friday weekend.
Zero warmup. Zero testing. Just flip the switch and pray.
I asked him one question: "What's your authentication setup look like?"
Silence.
"Uh... I think my ESP handles that?"
“Yeah… I don’t think so,” I told him.
You need to understand what happens when volume spikes meet mailbox provider filters during the busiest email weekend of the year.
This year, I brought Matt Vernhout onto Audience Bridge Insights to break it all down.
Why Matt?
Matt's been in email deliverability for over 20 years. He's Principal Consultant at Email Industries, founder of EmailKarma, co-chair of the BIMI Working Group, and sits on advisory boards for CAUCE, M3AAWG, and a handful of other organizations shaping email policy and anti-abuse standards.
Translation: He knows what mailbox providers are looking at before your Black Friday campaign even lands.
I needed someone who could break down what actually destroys deliverability during high-volume periods—not the surface-level "warm up your IPs" advice, but the technical infrastructure mistakes that silently tank inbox placement when stakes are highest.
What I got was a masterclass in avoiding the deliverability meltdowns that cost publishers and brands millions every Q4.
Here's what we uncovered:
The 10 Things You Need to Fix Before Black Friday (Or You'll Spend January Repairing Your Reputation)
1. Your Biggest Problem Isn't Your Copy—It's Your Data
Matt didn't hesitate on this one.
"Your biggest problem is your data. Not your copy. Not your ESP. Not Gmail 'getting stricter.' It's your data collection, data maintenance, and the fact that you keep sending to people who haven't engaged in months."
Email deliverability doesn't collapse overnight—it erodes from neglect.
He sees it every year: Brands grab their entire database for Black Friday, blast everyone including subscribers who haven't opened in 18 months, and wonder why their inbox placement tanked.
"I can't tell you how many brands I've worked with over the years that Black Friday comes up and then in January we're doing nothing but reputation repair," he said. "Because they just blow it up for the entire month of December."
2. Stop Obsessing About Gmail Promotions vs. Primary
This one's controversial, but Matt was clear:
"Promotions is still the inbox. Consumers read it. They use it."
In fact, when brands force their way into Primary by gaming the system, they get more spam complaints—not more engagement.
"Consumers have learned promotions should be in the promotions tab," he said. "If you spend all this time fighting to get it in the primary tab, consumers don't like that either."
The goal isn't Primary. The goal is consistent inboxing with predictable reach.
If your opens, clicks, and revenue aren't dropping—you don't have a Promotions problem.
3. Authentication Now Matters More Than Ever (And It's Only Getting Stricter)
SPF → DKIM → DMARC aren't "best practices" anymore.
They're the cost of entry.
"Gmail has come out even recently saying we're going to get more picky about authentication and start returning soft bounces and hard bounce codes for poorly authenticated mail."
Translation: They're not even going to waste resources scanning your email if you can't get authentication right.
And here's what's coming that most senders aren't preparing for:
DKIM2 and DMARCbis—massive upgrades to authentication that may eventually make SPF obsolete and eliminate the replay/spoofing issues that plague current DKIM.
"If you aren't DMARC aligned now, the next 12-18 months are going to hurt," he said.
4. Warmup Services: Useful Short-Term, Deadly Long-Term
I asked Matt about all these warmup tools flooding the market.
"Warmup tools can help short-term when used responsibly—but mailbox providers are getting extremely good at detecting fake engagement."
If you rely on warmup long-term:
You're propping up a weak sending program
Your signals aren't real
And you're eventually going to get crushed
Warmup ≠ Strategy. Warmup = Crutch.
5. Domain Reputation Now Matters More Than IP Reputation
This one's critical for anyone switching ESPs:
Your domain reputation follows you. Your IP reputation doesn't.
That means two things:
If your domain is bad, moving ESPs won't fix you
If your domain is great, switching ESPs won't punish you
"Watch your domain like it's your credit score," Matt said.
6. Cross-Contamination Is Silently Killing Your Deliverability
One of the most eye-opening parts of our conversation:
Teams often sabotage each other without knowing it.
Examples Matt's seen:
Sales sending cold outreach from the same root domain as marketing
Support blasting from a subdomain no one monitors
Zoom/webinar invites going out unauthenticated
Old apps or tools sending system emails no one remembers exist
"These bleed reputation across your domain and subdomains," he said. "If you're seeing unexplained deliverability drops, this is your first place to investigate."
I've seen this destroy newsletter operators who start cold emailing advertisers from the same domain they send their newsletter from. Reputation tanks across everything.
7. New Subscribers Are Your Most Important (And Most Dangerous) Segment
Matt considers new subscribers (0-30 days) the most sensitive segment.
"If they don't engage, mailbox providers notice immediately—and you get punished."
His advice:
Send a welcome series
Give them early chances to engage
Don't bury them in frequency
Don't throw them into full blasts until they've proven responsive
He told me about a recent test where someone subscribed with two email addresses to the same sender. Engaged with one welcome email, did nothing with the other.
The second set of emails: The engaged address went to inbox. The non-engaged address went to spam.
"Mailbox providers are looking to say, did you engage with this ever?" he said. "And if so, making adjustments."
8. Your Winback Strategy Is Probably Destroying Your Domain
Most brands do reactivation wrong.
They grab 50,000 non-engaged subscribers and hit "send."
That is how you burn a domain down.
Matt's recommendations:
Automate winbacks—never do one big blast
Small daily drips
Never more than 10% of your active send volume
Expect only 2-5% to return
"If your winback strategy feels too big, too fast, or too loud... you're doing it wrong."
9. Inbox Monitoring Tools: Useful, But Not Gospel
"Mailbox providers personalize filtering per user," Matt explained. "Your Gmail ≠ my Gmail."
Seed tests are best used as a heartbeat, not a decision engine.
Use them to catch major shifts—not to test every single campaign before you send it.
"If you're 100% inboxing according to seed testing 10 weeks in a row and then week 11 you're 50% inboxing, well, what happened in the last week or two that maybe has impacted your reputation?" he said. "There's certainly an indicator there."
But don't base your entire strategy on what seeds tell you.
10. Matt's Black Friday Survival Checklist (Read This Twice)
Before Black Friday hits:
✅ Warm up now—don't wait. Don't go from 10K to 500K overnight.
✅ Validate the data you're about to upload. Hygiene your list before volume spikes.
✅ Confirm SPF/DKIM/DMARC are correct. Test authentication before you need it.
✅ Avoid giant volume spikes—ramp gradually. Mailbox providers hate variance.
✅ Fix your new user onboarding. Get them engaging before Black Friday.
✅ Watch your complaint rate like a hawk. Use Yahoo Sender Hub to monitor in real-time.
Missing even one of these can put you into January-Is-Spent-Repairing mode.
What This All Means
Email deliverability during Black Friday isn't about getting lucky.
It's about infrastructure, authentication, data hygiene, and gradual volume ramping.
Matt's been doing this for 20+ years. He's seen every mistake publishers and brands make during Q4. And the pattern is always the same:
They optimize for short-term volume at the expense of long-term reputation.
Then they spend January trying to repair what they broke in November.
Don't be that publisher.
🚨Want to make sure your infrastructure is ready for Black Friday volume?
I'm opening up 5 Free Deliverability Audit calls this week.
We'll look at your authentication setup, check for cross-contamination issues, review your segment strategy, and map out exactly what you need to fix before volume spikes hit.
(If you're planning to increase send volume by more than 50% in the next 30 days and haven't validated your authentication or list hygiene recently, you need this call.)
Don’t put all your eggs into Black Friday.
Spread it out,
Chris Miquel
PS: Remember that publisher who was going to spike from 10K to 500K on Black Friday with no warmup? He's ramping gradually now, starting two weeks out. Could've been a disaster. Instead, he'll actually see his emails land.
BEFORE YOU GO
Listen to the Full Episode
This is just the surface. The full conversation with Matt Vernhout is packed with tactical advice on avoiding the deliverability disasters that destroy Q4 revenue.
🎧 Listen now 👈
