Double Opt-In (DOI)
Double Opt-In (DOI)
- April 20, 2021
- Posted by: Nicola Selenu

A process for confirming that recipients want your email. Involves recipients confirming their subscription via a form, email, clicking a link, or other means.
- Spam Resource: Wombatmail COI/DOI update: Now with reCAPTCHA!
- Sendingblue: What Is Double Opt-In? Why You Need It & How to Set It Up.
- Spam Resource: Does Germany require COI/DOI? (Updated for 2022)
- Sendingblue: 9 Best Email Autoresponders in 2022 [Free and Paid]
- Spam Resource: Chad S. White: 4 Ways to Maximize Double Opt-In Confirmations for Email
Author:Nicola Selenu
Email Service Providers Handbook
The most comprehensive “Handbook of Email Service Providers“!
SPAMASSASSIN RULES
All SpamAssassin rules in one place, EXPLAINED!
SMTP COMMANDS
& REPLY CODES
All SMTP/ESMTP commands and reply codes in one place, EXPLAINED!
Free DNS Tool
Check the DNS records of your domain with our free DNS tool.
Deliverability Glossary
The most comprehensive Email Deliverability and Marketing Glossary!
- Spam Resource: Wombatmail COI/DOI update: Now with reCAPTCHA!
- Sendingblue: What Is Double Opt-In? Why You Need It & How to Set It Up.
- Spam Resource: Does Germany require COI/DOI? (Updated for 2022)
- Sendingblue: 9 Best Email Autoresponders in 2022 [Free and Paid]
- Spam Resource: Chad S. White: 4 Ways to Maximize Double Opt-In Confirmations for Email
Double Opt-In (DOI)
A process for confirming that recipients want your email. Involves recipients confirming their subscription via a form, email, clicking a link, or other means.
Author:Nicola Selenu
Email Service Providers Handbook
The most comprehensive “Handbook of Email Service Providers“!
SPAMASSASSIN RULES
All SpamAssassin rules in one place, EXPLAINED!
SMTP COMMANDS
& REPLY CODES
All SMTP/ESMTP commands and reply codes in one place, EXPLAINED!
Free DNS Tool
Check the DNS records of your domain with our free DNS tool.
Deliverability Glossary
The most comprehensive Email Deliverability and Marketing Glossary!