Koukan is an email/application gateway.
Koukan provides mail transfer agent (MTA) and mail submission agent (MSA) functionality for existing applications that expect SMTP store&forward semantics.
Koukan provides a rich HTTP/JSON REST api for new applications. The api includes rfc822/MIME format handling which has uneven support across programming languages/frameworks.
Koukan is targeting on-premises/self-hosted use cases where software-as-a-service (SAAS) isn't a good fit and you want the email stack local to the application.
Key features:
- opportunistic cut-through delivery: synchronous reporting of common-case errors rather than accept&bounce
- compatible with horizontal scaling on multi-node/cluster/Kubernetes environments
- extensible via plugin api inspired by Envoy filter chains. Koukan aspires to be "Envoy for email."
Koukan is written in Python3 leveraging high-quality Python implementations of email technical standards/RFCs that already exist such as smtplib, aiosmtpd, email, and dkimpy.