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Courier Mail Server vs Apache James: catalog facts
Courier Mail Server	Apache James
Free Free and open-source software.	Free Free and open source from the Apache Software Foundation.
Linux, Self-hosted	Self-hosted
SMTP, IMAP, POP3, webmail and mailing lists in one package Components can be switched on or off individually	Supports modern JMAP alongside SMTP, IMAP and POP3 Mailet container for custom mail processing
Built from source on POSIX systems, with no Windows support Calendaring in the webmail is basic	Requires a Java runtime and some server administration knowledge Distributed setups depend on extra services such as Cassandra
Self-hosted	Self-hosted
Open source	Open source
License not stated	License: Apache-2.0
No account needed	No account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.