Blog
Email Deliverability Guides & Best Practices
Guides, best practices, and intelligence from the InboxEagle team to help you land in the inbox every time.
Authentication8 min
How Domain Alignment Affects Inbox Placement in 2026
Domain alignment is why your emails fail DMARC even with valid SPF and DKIM — here's what's breaking and how to fix it.
Authentication6 min
Does DMARC Failure Guarantee the Spam Folder? A 2M Email Study
We analyzed 2.2 million emails to find out if DMARC failure sends you straight to spam. The answer is more nuanced, and more actionable, than you'd expect.
Authentication6 min
The State of Email Authentication: SPF/DKIM Adoption in Ecommerce
Email authentication adoption in ecommerce leads every other industry — yet most brands still run DMARC at p=none. Here's what the 2025/2026 data says and where the real gap is.
Gmail7 min
Gmail Deliverability Benchmarks for Ecommerce Brands: Q1 2026 Data
InboxEagle monitored 721,351 emails to Gmail in Q1 2026. Here are the real gmail deliverability benchmarks — spam rates, tab placement, and what separates healthy programs from at-risk ones.
E-commerce6 min
The Ecommerce Email Deliverability Gap: What Top Brands Do Differently
InboxEagle analyzed 3,474 ecommerce sender domains and found a 72-point inbox placement gap between the best and worst performers. Here's the ecommerce email performance benchmark — and what separates top-quartile brands from everyone else.
E-commerce6 min
Do Aggressive Sale Subject Lines Hurt Deliverability? What Our Data Shows
Sale language doesn't automatically hurt deliverability — but some patterns do. InboxEagle analyzed 721,351 emails and found results that flip conventional wisdom on its head.
Authentication7 min
BIMI in 2026: Google's CMC Makes Brand Logos Affordable for Everyone
Google launched a Common Mark Certificate option for BIMI in 2025, no trademark required. Here's how BIMI works, what's changed, and whether it's worth implementing for your email program.
Gmail6 min
Microsoft Outlook's Bulk Sender Requirements: What Email Marketers Need to Know
Microsoft began enforcing bulk sender requirements for Outlook, Hotmail, and Live.com on May 5, 2025. Non-compliant mail gets a 550 5.7.515 rejection. Here's exactly what's required and how to comply.
E-commerce8 min
Ecommerce Email Benchmarks 2026: Inbox, Promotions & Spam
InboxEagle analyzed 721,351 ecommerce emails in Q1 2026. Here's where they landed — Primary, Promotions, and Spam — and what the data means for your sending program.
Gmail13 min
Where Your Email Lands: Inbox, Promotions, or Spam?
Most senders track delivered vs. spam. But Gmail has a third folder — the Promotions tab — that quietly buries marketing emails just as effectively. Here's what determines where your email lands, and how to see all three outcomes before you send.
Authentication3 min
Email Deliverability Checklist: 30 Pre-Send Checks
A complete pre-send checklist covering authentication, sender reputation, list hygiene, content, and monitoring — updated for 2026 enforcement requirements.
Gmail6 min
How Email Spam Filters Work: What ISPs Check Before Delivering Your Email
A technical but accessible explanation of how Gmail, Outlook, and Yahoo decide whether your email reaches the inbox or the spam folder.