Difficulty of reading scholarly papers is significantly reduced by reader-friendly writing principles. Writing reader-friendly text, however, is challenging due to difficulty in recognizing problems in one’s own writing. To help scholars identify and correct potential writing problems, we introduce SWAN (Scientific Writing AssistaNt) tool. SWAN is a rule-based system that gives feedback based on various quality metrics based on years of experience from scientific writing classes including 960 scientists of various backgrounds: life sciences, engineering sciences and economics. .