lu­a­tex – The LuaTeX en­gine

LuaTeX is an ex­tended ver­sion of pdfTeX us­ing Lua as an em­bed­ded script­ing lan­guage. The LuaTeX project’s main ob­jec­tive is to pro­vide an open and con­fig­urable vari­ant of TeX while at the same time of­fer­ing down­ward com­pat­i­bil­ity.
LuaTeX uses Uni­code (as UTF-8) as its de­fault in­put en­cod­ing, and is able to use mod­ern (OpenType) fonts (for both text and math­e­mat­ics).
It should be noted that LuaTeX is still un­der de­vel­op­ment; its spec­i­fi­ca­tion has been de­clared sta­ble, but ab­so­lute sta­bil­ity may not in prac­tice be as­sumed.