SMTP Codes
smtp.codes is a collection of SMTP response codes returned by email servers and a guide to help you understand what the SMTP codes that various email servers respond with mean.
This is super useful when troubleshooting email delivery and a tool every email marketer, deliverability person or email engineer should have in their tool kit. We welcome all contributions!
Codes
Providers
- Amazon Simple Email Service
- AT&T
- Barracuda
- Cisco
- Comcast
- Email Security.cloud
- Exchange Online Protection
- FireEye
- Free
- GMX
- GoDaddy
- HEY
- Hostpoint
- iCloud
- ImprovMX
- Infomaniak
- Mail.ru
- Mimecast
- MXroute
- Orange
- Outlook.com
- Proofpoint
- Proton Mail
- Rackspace
- Rambler
- Trend Micro
- t-online
- Web.de
- Yahoo
- Yandex
- ZeroSpam
- Zoho