Sorting and filing email messages with absolute precision and safety.

Pigeonhole adds Sieve mail filtering and the ManageSieve protocol to Dovecot. Securely compile and execute mail filters at delivery time, keeping your mail store organized and safe.

Key Features

Built with reliability and extensibility at its core, mimicking Dovecot's robust design.

Common error messages are made as clear as possible. The compiler reports multiple script errors at once to make debugging more efficient.

Modular design supports third-party Sieve capability plugins through a generic extension interface without changes to core engine code.

Completely backwards compatible with the legacy CMUSieve plugin, including support for deprecated Sieve extensions when enabled.

Supports executing multiple Sieve scripts sequentially. Admins can run scripts before and after personal user scripts safely.

Includes an extensible test suite written as a Sieve language extension, ensuring reliable execution and compiler correctness.

Ships with the sieve-test tool, a command-line utility that simplifies compiling, executing, and debugging Sieve scripts locally.

Pigeonhole is open source, distributed under the LGPLv2.1 license.