I've been hearing and reading this line of thinking a lot and I wanted to open up a real conversation about what's changed, what's noise, and what's actually worth doing differently. Keep reading to get my take and then let me know your thoughts.
TL;DR – some things are genuinely harder. But the fundamentals that drive email success haven't changed. The brands winning right now are the ones who cleaned up their lists, tightened their segments, and stopped treating "delivered" as the finish line.
What's genuinely more difficult now
Three things legitimately shifted in the past 18 months.
Inbox providers are enforcing stricter standards. Gmail and Yahoo now require proper authentication for bulk senders, so SPF, DKIM, and DMARC alignment are mandatory, not optional. One-click unsubscribe is required for marketing emails. Google's sender guidelines FAQ details current enforcement, and Microsoft Outlook followed with its own requirements in May 2025. If your bounce rate climbs above 3% or complaint rate exceeds 0.3%, you'll get throttled or blocked. You can't fake your way to the inbox anymore.
"Delivered" doesn't mean "in the inbox." Your ESP might report a message as delivered, but inbox providers use engagement history to determine where it lands. If a subscriber rarely opens your emails, future messages are more likely to end up in Promotions or get silently filtered. Every send to a non-engaged subscriber trains Gmail and Yahoo that your emails aren't wanted, and that pattern affects where your future emails land, including for your best customers.
Low-quality signups hurt faster and harder. Incentive-driven captures (big discounts, giveaways, email-gated content) produce subscribers who rarely engage. Bots, typos, and fake emails are also more common as acquisition costs rise. If you're seeing 5%+ bounce rates on new signups, your capture process is letting garbage through. Prevention is now more valuable than cleaning after the damage is done.
What hasn't changed
The brands struggling in 2026 are mostly the ones who were cutting corners before. The ones thriving were already doing the fundamentals, and just tightened execution.
Relevance still wins. Personalized, timely messages based on real behavior (i.e. browse abandonment, post-purchase, and win-back) still convert at high rates. If you're sending generic blasts to your full list, you're competing with every other generic blast in the inbox. Targeted sends based on what someone actually did are in a different category entirely.
Engagement protects deliverability. Sending to people who actually want to hear from you has always been the right move. Now it's the only sustainable one. Inbox providers reward senders whose emails get opened and clicked if your list is full of cold subscribers, you're actively training Gmail and Yahoo that your emails aren't relevant.
Testing and iteration still compound. Brands that run disciplined A/B tests on subject lines, send times, offers, and segments and act on the results see steady lift. This isn't new – it's just more important now because the margin for error is smaller.
Your owned list is still your most valuable asset. Email remains the highest-ROI channel for most DTC and retail brands. What changed is that the brands treating email like a performance channel (not a broadcast channel) are pulling further ahead.
4 things you can do to protect email revenue in 2026
You don't need to overhaul everything at once. Here are the moves that matter most, in order of priority.
1. Tighten your engaged segments and stop sending to everyone
Create engagement-based segments that exclude subscribers who haven't opened or clicked in 90–180 days, depending on your send frequency. Sending to people who never open trains Gmail and Yahoo that your emails aren't wanted and that hurts deliverability for everyone on your list, including your most engaged customers.
In Klaviyo, build a core engaged segment using conditions like: Opened Email at least once in the last 90 days OR Clicked Email at least once in the last 90 days OR Placed Order at least once in the last 90 days. Use this as your default campaign audience. For cold subscribers (180+ days of no engagement), run them through a sunset flow before suppressing – it's a last-chance win-back before you let them go. You can also use the Deliverability hub to surface a Never Engaged segment automatically.
Good benchmarks: open rates above 20% and bounce rates below 1%. If you're under those, your engaged segment definition is too loose or you have a list quality problem to fix first.
2. Validate emails at the point of capture, before they hit your list
Cleaning your list after the fact is reactive. Prevention protects your sender reputation from day one. Klaviyo signup forms include built-in email validation that catches syntax errors and common typos like "gmial.com" or "yahooo.com", so you can block bad emails without adding friction to signup. For high-risk sources like paid social, giveaways, or influencer traffic, double opt-in is worth the tradeoff.
In your welcome flow, send the first email immediately (with any promised incentive) and use engagement on that first message as a signal. Non-openers can be suppressed or moved to a slower cadence.
Good benchmarks: bounce rates on new subscribers below 2%, welcome flow open rates above 40%. If you're seeing 5%+ bounces on new signups, the capture process is the problem.
3. Audit your authentication and sending domain setup
Confirm that your SPF, DKIM, and DMARC records are properly configured and that you're sending from a consistent, dedicated subdomain (not a shared or frequently-changing domain). Gmail and Yahoo require this for bulk senders, and enforcement has only tightened since 2024.
In Klaviyo, go to Settings > Email > Sending Domain and confirm your domain is verified. Check that DKIM is enabled and your DMARC policy is set (p=none is fine to start). If you're sending from multiple subdomains, consolidate to one dedicated subdomain like send.yourbrand.com to build consistent reputation. Klaviyo's email authentication guide covers everything you need and if you're unsure about your current setup, send a test to a Gmail account and check the message headers.
4. Treat new subscribers differently for the first 30 days
Inbox providers form an opinion about your emails fast. If a new subscriber ignores your first 3–5 messages, continuing to send trains their inbox that your emails aren't relevant — and that signal sticks.
In Klaviyo, use conditional splits in your welcome series based on engagement. If someone opens or clicks message 1, send message 2 immediately. If they don't, wait 3–5 days or move them to a slower nurture track. After the series, limit campaign sends to 1–2x per week for the first 30 days, and suppress non-engagers from campaigns entirely until they take an action like browsing, clicking, or purchasing.
Good benchmarks: welcome series open rates above 35%, click rates above 5%. If your welcome series is underperforming, the issue is usually list quality or relevance, not the emails themselves.
Your next step, based on where you are
Pick one move and run it this week.
- Bounce rate above 2% or seeing "emails blocked" errors? Start with Move 3 (authentication audit) and Move 2 (validation at capture). Your sender reputation is at risk. Fixing authentication protects you immediately, and validation prevents future problems.
- Open rates declining but authentication is solid? Start with Move 1 (tighten engaged segments) and Move 4 (new subscriber ramp). You have a list quality or relevance issue, not a technical one.
- Not sure where the problem is? In Klaviyo, segment your list by engagement level (0–30 days, 31–90 days, 91–180 days, 180+ days) and see where the drop-off happens. That tells you whether it's a list quality problem or a content and relevance problem.
What to ignore
Three things dominate inbox placement conversations but won't actually move the needle: obsessing over blacklist checks (they're usually a symptom of list quality issues, not the cause), chasing "perfect" send times (relevance matters more than 10:03 a.m. vs. 10:17 a.m.), and worrying that iOS Mail Privacy Protection broke email (opens are noisier, but clicks and revenue per recipient are still accurate and adjust your metrics and keep going).
If your list is clean, your content is relevant, and you're sending to engaged subscribers, you're already doing the work that matters.
What are you seeing?
Do you feel like things are more difficult these days? If so, why? And do you have advice to share with others to make the new modern inbox game less daunting?
Additional Resources
- How to clean your email list to maintain good deliverability
- How to create a sunset flow
- How to create an engaged email segment
- Advanced segmentation strategies
- Understanding email authentication (SPF, DKIM, DMARC)
- Authenticate your emails with a branded sending domain
- Gmail email sender guidelines
- Google's email sender guidelines FAQ
- Engaged segments
- Best practices for sunset flows — community discussion
