What is Flatcurve?

Important Note

FTS Flatcurve will become the default Dovecot Community Edition (CE) FTS driver in v2.4 (merged into Dovecot core in April 2022).

FTS Flatcurve will continued to be maintained separately in GitHub for backwards support with Dovecot CE v2.3.x. However, it is possible that configuration and features may differ between this v2.3 code and core v2.4 code.

This is a Dovecot FTS (Full Text Search) plugin to enable message indexing using the Xapian Open Source Search Engine Library.

The plugin relies on Dovecot to do the necessary stemming. It is intended to act as a simple interface to the Xapian storage/search query functionality.

This driver supports match scoring and substring matches, which means it is RFC 3501 (IMAP4rev1) compliant (although substring searches are off by default). This driver does not support fuzzy searches, as there is no built-in support in Xapian for it.

The driver passes all of the ImapTest search tests.