Bounce codes and SMTP errors explained
Async Bounce vs Synchronous Rejection: What You Need to Know
Differentiate between asynchronous bounces and synchronous rejections to reduce delivery failures.
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Field notes on deliverability.
Hard-won lessons on email verification, inbox placement, and keeping your sender reputation spotless — from the team that's been verifying email since 2000.
Email deliverability fundamentals and best practices
New Template Causing Spam Placement? How to Test
Identify why a new email template is triggering spam filters. Test inbox placement and deliverability risks before sending to your entire list.
Email deliverability fundamentals and best practices
How to Scan an Email for Invisible Characters Before Sending
Detect hidden characters in emails before sending with a real-time email verification tool. Prevent bounces, spam flags, and deliverability issues caused.
Anti-spam laws and compliance: CAN-SPAM, GDPR, CASL
Can-Spam Transactional vs Commercial: Primary Purpose Test Explained
Understand the Can-Spam primary purpose test for transactional vs commercial emails. Reduce bounces, avoid spam filters, and improve inbox placement with.
Inbox placement by mailbox provider: Gmail, Outlook, Yahoo and spam filters
iG Mail Deliverability and Account Purges in Brazil 2026
Fix iG.com.br email deliverability issues and prevent account purges in Brazil. Clean your list with real-time verification and inbox placement tests.
Sender reputation, IP warm-up and sending infrastructure
Notification Email Frequency Caps Per User Per Day in 2026
Control notification email frequency caps per user per day to reduce bounces and improve inbox placement.
Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS
DANE for SMTP Explained: How TLSA Records Secure Mail Transport
Learn how DANE for SMTP uses TLSA records to secure email transport. Understand DNS-based authentication, TLS encryption, and reduce man-in-the-middle.
Email blocklists: monitoring, causes and delisting
Orange Abuse Postmaster Delisting Request Process 2026
Learn the exact Orange abuse postmaster delisting request process. Reduce bounce rates and improve deliverability with actionable steps for IP reputation.
Sender reputation, IP warm-up and sending infrastructure
SendGrid Subuser Reputation Isolation in 2026
Prevent one client's bad behavior from affecting others. Learn how SendGrid subuser reputation isolation works and how to verify your email list for.
Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS
What Is a BIMI Common Mark Certificate CMC? 2026
Understand what a BIMI Common Mark Certificate (CMC) is and how it improves brand trust and inbox placement.
Sender reputation, IP warm-up and sending infrastructure
Reputation Monitoring vs Placement Monitoring: Key Differences in 2026
Understand the real difference between reputation monitoring and placement monitoring. Improve inbox placement and sender health with actionable insights.
Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS
DMARC Relaxed Alignment Subdomain Example: mail.example.com
Learn how DMARC relaxed alignment works with subdomains like mail.example.com. See real-world examples, common issues, and how to verify email validity.
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Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.