BFCM Email Deliverability Best Practices

As the age-old saying goes, your Black Friday and Cyber Monday (BFCM) campaigns are only as strong as your deliverability. Sending more emails means nothing if they end up in the Promotions or Spam folders. Why? Because then your customers just won’t see them.

We asked our retention experts how they prepare client domains, IPs, and reputations for BFCM volume. Here’s their playbook for deliverability that drives clicks, opens, and sales.

Spamageddon: The Usual Deliverability Nightmares

Deliverability challenges pile up during BFCM. These are the traps we see most often:

• Sudden spikes in volume: If a brand hasn’t been mailing consistently, a sharp jump in sends often triggers Internet Service Provider (ISP) filters.
• Blasting the full list: Mailing too many unengaged contacts tanks metrics and damages domain reputation, even with new or engaged subscribers.
• Shared IP pools: On Klaviyo and most ESPs, your deliverability can dip if others on the same pool blast poor-quality lists.

Don’t Shock the Inbox: Prepping Domains and IPs

ISPs reward consistency. Ramp up early and carefully to keep your reputation intact:

• Re-engagement push: Run this 1–2 months before BFCM so there’s time to recover and build a good sending reputation if needed.
• Smaller batches: Reach unengaged subscribers in stages, not all at once.
• Balance with engaged sends: Keep emailing active customers to offset weaker signals.
• No sudden segment boosts: Widen segments step by step, leading into the main BFCM sends.
• Do what ISPs like: This includes things like plain-text emails, reply requests with a real reason, prompts to move you into the Primary tab, and engaging content or offers that drive clicks.

Inbox Foreplay: Domain Warming That Works

Warming is about trust. Show ISPs you can handle volume without spamming:

• Start widening audiences early: Increase your send sizes gradually instead of jumping from small lists to your full database overnight.
• Balance engaged with less-engaged contacts: Always mix in highly active profiles to keep your overall engagement rates strong.
• Use engagement-driven content: Early-bird access, interactive prompts, or special offers encourage opens and clicks that boost sender reputation.

Big Brother is Watching: Monitoring Reputation

Reputation can change fast during BFCM. Stay proactive, not reactive:

• Use deliverability tools like the Glock Spam Test: Check how your emails place across different inboxes before and during the sales period.
• Review results inside Klaviyo (or your ESP): After each send, dig into the deliverability tab to see if inbox placement is slipping.
• Look beyond top-line metrics: Opens and clicks give signals, but you also need to monitor bounce rates, unsubscribes, and complaint levels.
• Analyze ISP-level performance: Break down results by Gmail, Yahoo, and others to identify provider-specific issues and adjust targeting quickly.

Stress Test: Deliverability Checks Before Sending

Don’t wait until Black Friday morning to find out your emails land in Spam. Test them first:

• Run spam placement tests: Use deliverability tools to preview inbox placement for upcoming campaigns before sending at scale.
• Test subject lines carefully: Avoid spam triggers like all caps, heavy emoji use, or over-the-top “salesy” words that can trip filters.
• Send plain-text versions when needed: Balance image-heavy or promotional emails with simpler text-based sends to keep your engagement levels stable.
• Encourage replies and inbox actions: Ask readers to reply, or prompt them to drag your emails to Primary, both of which signal trust to ISPs.

Damaged Goods: Handling Existing Issues

Already have deliverability problems? Playing it safe now can make a huge difference:

• Don’t blast more during BFCM: Pushing harder might give you one or two decent campaigns, but the long-term damage can take six months to repair.
• Clean your list if it’s overdue: Remove inactive contacts, bounces, and complainers so only engaged subscribers receive your offers.
• Audit subject lines and formatting: Reduce the use of spammy words, excessive caps, or design tricks that can trigger filters and negatively impact inbox placement.
• Lean on plain-text sends: They feel more personal, reduce filter risk, and often earn stronger replies than overly designed emails.
• Use response-based sends: Give people a reason to reply or interact, like asking for feedback or confirming interest in deals.
• Send content people care about: Campaigns with real value drive opens and clicks that help rebuild reputation over time.

ISP Watch: Provider-Specific Tips

Not all inboxes behave the same. Track each one separately and keep the following in mind:

• Gmail: Sensitive to sudden spikes in volume and very quick to react to spam complaints. Keep segments tight and reward engagement.
• Yahoo: More tolerant of volume increases but harsher when complaint rates rise, so keep your messaging relevant to avoid sudden filtering.
• All ISPs: Use Klaviyo reporting to check how each provider handles your sends. Adjust audiences or creative for weak spots before scaling campaigns.

Hope is Not a Deliverability Plan

Clean offers won’t save dirty signals. Respect ISP limits, warm gradually, and protect your sender reputation. Do that, and when the big weekend arrives, your campaigns will be seen where they belong, in your customers’ inboxes.

Our experts have guided dozens of brands through BFCM deliverability. 

Book a call and let us set you up for success.