Gmail & Google Postmaster Guides
Understand Gmail's spam filters, monitor your domain reputation, and take action when your inbox placement drops.
Gmail16 min
Why Are My Emails Going to Spam? 12 Ways to Fix It
Why emails go to spam and how to fix it — 12 systematic checks covering authentication, sender reputation, bounces, complaints, audience quality and inbox placement, plus how InboxEagle helps you investigate.
Gmail6 min
Gmail Bulk Sender Requirements: What You Need to Know in 2026
Gmail has enforced bulk sender requirements since February 2024, and ramped up to temporary and permanent rejections in November 2025. Here's exactly what the DMARC requirement means, and how to check whether you're actually compliant.
Gmail3 min
Bounce Rate vs Complaint Rate: Which Hurts More
Bounces mean the server did not accept the mail. Complaints mean a person marked accepted mail as spam. Which one is more dangerous depends on the provider measuring it.
Gmail6 min
Gmail Deliverability Troubleshooting Guide
Gmail can accept a campaign and still file it in spam. This is the order to check Compliance status, the Postmaster spam rate, and authentication before you rewrite the creative or change ESPs.
Gmail3 min
How to Monitor Deliverability at Gmail, Yahoo, and Outlook
Gmail, Yahoo, and Outlook do not share one dashboard. Here is which official tool covers which signal, and what a seed test adds for Gmail, Yahoo, AOL, and Outlook.
Gmail4 min
Why Order Confirmation Emails Go to Spam
Order mail goes to spam when it shares a reputation with marketing, or when the transactional sender is not authenticated. Here is how to tell those apart and keep receipts delivering.
Gmail3 min
Why Inbox Placement Differs by Mailbox Provider
The same campaign can hit the Gmail inbox, Yahoo spam, and an Outlook rejection. Here is how to tell a provider-specific problem from a broken program.
Gmail4 min
How Long Sender Reputation Takes to Recover
Mailbox providers do not publish a recovery clock for IP or domain reputation. Here is what is actually documented, and what to do while you wait.
Gmail8 min
Why Are My Emails Suddenly Going to Spam?
A sudden move to the spam folder is a diagnosis problem, not a subject-line problem. Here is how an eCommerce sender works out whether authentication, complaints, list quality, or a provider filter caused it, and how to confirm the fix.
Gmail9 min
Gmail Emails Going to Spam? What 514K Messages Show
Your ESP dashboard says delivered. Then you check Gmail and find it in Spam. We tracked 514,492 Gmail-bound ecommerce messages between 11 June and 11 September 2026: 25% landed in spam, and unauthenticated mail was more than twice as likely to get filtered. Here's what actually moves the needle — authentication, ESP choice, and sending volume — and what a blended, all-provider dashboard hides about your Gmail-specific problem.
Gmail9 min
List-Unsubscribe Header: Does It Actually Reduce Spam Rates?
Does the List-Unsubscribe header actually lower spam rates? InboxEagle's study of 19,797 brands reveals a 4.86x extreme spam risk for senders without it.
Gmail8 min
The Correlation Between High Sending Frequency & Spam Complaints
Does sending more emails mean more spam complaints? InboxEagle analyzed 31,586 sending programs — the data tells a more nuanced story than you think.
Gmail8 min
Gmail Spam Rate Thresholds: What 0.10% and 0.30% Actually Mean for You
Google sets two spam rate numbers that most senders misread. Here's exactly what 0.10% and 0.30% mean, how they're measured, and what to do before you breach either one.
Gmail8 min
Gmail Promotions vs Spam: Where 671K Ecommerce Emails Landed
We measured Gmail placement for 671,329 emails across ~19,400 ecommerce senders in Q1 2026. Brand-level deliverability turns out to be close to binary — and the middle ground barely exists.
Gmail8 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.
Gmail8 min
BIMI CMC Certificate in 2026: Cost, Rules and Setup
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.
Gmail7 min
Outlook 550 5.7.515: What It Means and How to Fix It
Microsoft returns 550 5.7.515 when the domain in the From address fails Outlook.com's high-volume authentication rules. The message is rejected. Here is the definition Microsoft publishes, and the checks that match it.
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.
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.
Gmail8 min
Google Postmaster Tools v2: The Complete Setup and Interpretation Guide
How to set up Google Postmaster Tools v2, read the Compliance status dashboard and its Deliverability analysis verdict, and plan for the reputation scores Google has said it will retire.