Sender Reputation Takes Center Stage as Email Filtering Intensifies

RIO DE JANEIRO, BRAZIL, November 13, 2026 /24-7PressRelease/ — Email filtering is preventing a significant share of messages from reaching recipients. An analysis of one billion emails processed in January 2026 found that 56.1% were blocked by spam and virus filters, while only 43.9% were delivered.

The findings, published in a 2026 email traffic study, cover different types of messages, including malicious traffic. They also identify poor sender reputation as a factor in 33.9% of rejected emails, followed by invalid recipient addresses and authentication issues among other causes.

For businesses that rely on email marketing, these findings point to the importance of maintaining healthy email lists, properly configured sending infrastructure, and a trustworthy sender reputation.

Gmail Sets Strict Requirements for Senders

Gmail recommends keeping user-reported spam complaint rates below 0.1% and preventing them from reaching 0.3%.

According to Google’s sender guidelines, elevated complaint rates can negatively affect inbox placement. Bulk senders with rates above 0.3% may also become ineligible for delivery issue mitigation.

Since November 2025, Gmail has progressively increased enforcement against messages that fail to meet its sender requirements, including temporary and permanent rejections.

“For years, businesses focused on increasing email volume without always paying the same attention to email list quality and message preparation. Today, having a good offer or relevant content is not enough. If sender reputation is compromised or an email contains technical issues, the entire investment in email marketing can go to waste,” says Priscila Gonçalves, CEO of SafetyMails.

Email Verification Is Only Part of the Process

Invalid, disposable, and potentially risky email addresses can lead to unnecessary bounces and other delivery problems. Email verification helps marketers identify problematic recipients before sending campaigns.

SafetyMails has studied these issues through its proprietary Email List Quality research, covering different business sectors.

However, valid recipient addresses alone cannot guarantee inbox placement. Authentication failures, message content, suspicious links, and technical configuration can also affect how emails are handled.

SafetyMails Introduces MailTester

In October 2026, SafetyMails officially launched MailTester, expanding its email verification services with a tool that analyzes messages before sending.

Users generate a dedicated test email address, send their message, and receive a technical report within minutes.

MailTester provides a spam risk score from 0 to 100, SPF, DKIM, DMARC, and BIMI authentication checks, SpamAssassin analysis, link and redirect evaluation, security checks, and desktop and mobile previews.

“Email verification is an essential step in reducing risks associated with recipients, but it is only one part of the process. With MailTester, we want to help marketing professionals identify potential problems before sending their emails, giving them more information to make decisions and protect deliverability,” Gonçalves explains.

Available to SafetyMails customers since October, MailTester uses the platform’s credit system, with each test consuming 100 credits. The tool helps identify potential technical and content-related issues but does not guarantee inbox placement or replace sender reputation monitoring.

About SafetyMails

SafetyMails is a Brazilian email verification company offering bulk email verification, real-time verification APIs, and email deliverability testing tools. Its 19-step verification process identifies invalid, disposable, and risky email addresses.

Website: https://www.safetymails.com/

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