layout title doc Compare Rspamd with other spam filters General Written in C/Lua Perl C Process model event driven pre-forked pool LDA and pre-forked MTA integration milter, LDA, custom milter, custom (Amavis) LDA Web interface embedded 3rd party Languages support full, UTF-8 conversion/normalisation, lemmatization naïve (ASCII lowercase) naïve Scripting support Lua API Perl plugins Licence Apache 2 Apache 2 GPL Development status very active active abandoned Mail filtering features Greylisting Ratelimit Replies whitelisting Rules composition Filtering methods Regular expressions filtering DKIM SPF DMARC with reports support 3rd party ARC Policies white and blacklists DNS lists URL DNS lists Phishing checks advanced with external resources very basic Custom lists with dynamic reload Pyzor Razor Own fuzzy storage DCC HTML rules own parser many regexp rules PDF filtering own parser Statistical methods Bayes classifier hidden Markov naïve hidden Markov Bayes autolearn with custom Lua rules + expiry by threshold Bayes window 5 words 1 word 2 words (5 words in SBPH/OSB mode) Plain files backend SQLite3 backend MySQL backend Redis backend Neural networks support via kann