Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS
How to Set Up CNAME-Based DKIM Delegation for Third-Party Senders
Learn how to securely delegate DKIM signing to third-party email providers using CNAME records.
Author
MailTester Editorial Team
Deliverability guides on inbox placement, spam testing and SPF, DKIM and DMARC from the MailTester team. Articles are researched and drafted with AI assistance and edited under our editorial policy.
How we write and check these articles →
3793 posts
Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS
DMARC Tree Walk vs Public Suffix List in Email Deliverability
Compare DMARC tree walk and traditional public suffix list methods. Learn how each impacts email deliverability, sender reputation, and inbox placement.
Cold email deliverability and warm-up
Does Hidden Tracking Text in Cold Emails Hurt Deliverability? 2026
Find out if hidden tracking text in cold emails affects inbox placement. Learn how MailTester's deliverability testing exposes risks before you send.
Inbox placement by mailbox provider: Gmail, Outlook, Yahoo and spam filters
Mail.ru Feedback Loop FBL Enable via Postmaster 2026
Learn how to enable Mail.ru's Feedback Loop (FBL) via Postmaster to improve deliverability, reduce spam complaints, and maintain sender reputation — with.
Sender reputation, IP warm-up and sending infrastructure
Gmail-Free Sender Reputation Tracking Dashboard for ESPs in 2026
Track sender reputation without relying on Gmail. Use real-time inbox placement tests and accurate email verification to improve deliverability and reduce.
Deliverability monitoring, metrics and reporting
Scheduled Email Reports with High Deliverability Using Email Validation
Ensure your scheduled email reports land in inboxes with reliable email validation. Cut bounce rates, boost sender reputation, and improve deliverability.
Inbox placement by mailbox provider: Gmail, Outlook, Yahoo and spam filters
Pulling Daily Postmaster Tools Data into Google Sheets 2026
Automate daily Postmaster Tools data collection into Google Sheets. Track sender reputation, inbox placement, and spam rates with real-time insights.
Sender reputation, IP warm-up and sending infrastructure
Automated Lookalike Domain Detection for Sender Reputation Management
Detect and block lookalike domains that harm sender reputation. Use MailTester’s real-time verification to identify risky addresses before they impact.
Email deliverability fundamentals and best practices
How to Audit Email Infrastructure for Dangling CNAMEs That Enable Subdomain Takeover
Discover how to detect and fix dangling CNAME records that enable subdomain takeover in your email infrastructure.
Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS
DMARC p=reject for Parked and Non-Sending Domains in 2026
Enforce DMARC p=reject on parked or non-sending domains to prevent spoofing and improve sender reputation.
Deliverability testing inside your ESP, CRM and sending platform
Adding Feedback-ID Header in SendGrid, Mailgun & Amazon SES
Learn how to add the Feedback-ID header in SendGrid, Mailgun, and Amazon SES to improve spam feedback tracking and sender reputation.
How to test email deliverability, spam score and rendering
Styled Alt Text That Displays When Images Are Blocked
Ensure accessible, on-brand email experiences when images are blocked. Learn how styled alt text improves deliverability and user engagement in 2026.