FontForge

FontForge is a free, open-source font editor supporting all common font formats including TrueType (TTF), OpenType (OTF), PostScript Type 1, SVG fonts, WOFF/WOFF2, UFO, and bitmap fonts (BDF, PCF). Created by George Williams in 2000, it has over 6,300 stars as of 2026. Key features include: a full glyph editor with bezier curve drawing tools, point manipulation (curve, corner, tangent points), TrueType and PostScript hinting support, OpenType feature editing (GSUB and GPOS tables for ligatures, kerning, contextual substitutions via visual editor or AFDKO syntax), metrics and kerning editing with kerning classes and auto-kerning, automatic outline operations (simplify, add extrema, remove overlap, correct direction), glyph transformations (scaling, rotating, shearing), font validation detecting self-intersecting paths and missing required glyphs, batch font conversion via scripting (native scripting language and Python module), multi-master and variable font support (creating OpenType variable fonts with weight, width, slant axes), and multi-format import/export. Written in C with Python scripting support.