Haraka vs Postal
No leader: the top candidate Haraka has only 0.31 confidence (low), below the 0.35 needed to declare a winner. The attribute-by-attribute breakdown below, with a source and date on every value, is the honest way to compare them.
Capabilities
Feature-by-feature on the axes that matter for email delivery infrastructure. “-” means undocumented, not absent.
What each one is
The product in its own terms, so the numbers below have context.
Haraka
A free, open-source SMTP server written in Node.js that efficiently handles thousands of concurrent email connections and allows developers to extend functionality through a modular plugin system written in JavaScript.
Postal
Not documented yet.
Pricing
List pricing as published by each vendor, with the date we read it. Always verify at the source before you buy.
Postal
Pricing not documented yet.
Platform & deployment
Where each product runs and how it can be hosted. A dash means undocumented, not unsupported.
Comparison generated from independently-sourced facts. Every value links to its source and retrieval date. See the method.