Test Email Deliverability: The Complete Guide Before Sending
One in five emails never reaches the inbox. This guide shows you how to test your email deliverability before sending and fix every issue.
Deliverability
Strategies to improve email inbox placement and sender reputation.
12 articles
March 2026
BIMI Without a VMC: The Budget-Friendly Guide to Displaying Your Logo in the Inbox
BIMI isn't just for large enterprises. This guide covers the 3 deployment tiers (free, CMC, VMC), the DNS prerequisites, and 5 steps for small and mid-sized businesses.
February 2026
Spamhaus vs Barracuda vs SpamCop: Complete Email Blocklist Comparison
Detailed comparison of the 3 main email blocklists: detection methods, false positive rates, delisting procedures, and impact on Gmail, Outlook, and Yahoo deliverability.
Why Your Emails End Up in Spam: The Complete Diagnostic Guide
Are your emails consistently landing in spam? This guide analyzes the 5 main causes and gives you a concrete action plan to restore optimal deliverability.
How to Remove Your IP from a Blacklist: The Complete Delisting Guide
Is your IP on a blacklist and your emails getting rejected? This guide details the delisting procedures for each major blacklist, including processing times and best practices to avoid getting listed again.
January 2026
Mailgun: Complete Technical Guide for Transactional Email
A detailed technical guide for developers: DNS configuration (SPF, 2048-bit DKIM with autorotation), REST API vs SMTP, dedicated vs shared IP, limits and webhooks.
Amazon SES: Complete Guide to DNS Configuration and Email Authentication
Complete Amazon SES configuration with Easy DKIM, Custom MAIL FROM, strict DMARC alignment. Everything you need for optimal deliverability and GDPR compliance.
December 2025
Connect CaptainDNS to ChatGPT via MCP: 3 widgets for DNS audits and deliverability
Add the CaptainDNS MCP server to ChatGPT and use 3 widgets to troubleshoot DMARC/DNS and analyze email headers without leaving the conversation.
BIMI, VMC, CMC: compatibility and DNS prerequisites (Gmail, Yahoo, Apple Mail)
Putting your logo in the inbox: what you actually need to configure in DNS for BIMI, and how to choose between VMC and CMC.
Gmail/Yahoo one-click unsubscribe: what RFC 8058 changes and how to implement it
Gmail and Yahoo require a one-click unsubscribe via RFC 8058-compliant List-Unsubscribe headers. Here's the expected format, the server-side POST, and the compliance checklist.
November 2025
BIMI logo cache: run a brand refresh and make the new logo show up everywhere
Your logo changed but inboxes still display the old one? It is not only a DNS issue: mailbox providers cache BIMI assets. Discover how the cache layers work and how to plan a smooth BIMI migration.
Gmail tightens its sending rules: what's changing for senders starting November 2025
Starting in November 2025, Google enforces new security requirements for bulk senders: full SPF/DKIM/DMARC authentication, TLS encryption and strict unsubscribe management.