Main examples of external typesetters include MacTeX/TeXLive and MikTeX. These primary provide the following chains,
pdfLaTeX: Used to generate most documents in PDF from LaTeX source.
XeLaTeX: Runs XeLaTeX to generate a PDF.
LuaLaTeX: This is a version of pdfTeX with a Lua scripting engine embedded. It is modern and capable of typesetting a large class of LaTeX documents.
A typeset may additionally require compilation of bibliographies, indices, processing of R code (within your RNW files) and other formats within your LaTeX code. A bibliography engine is a tool that manages your reference files. It is entirely optional as LaTeX is perfectly capable of producing citations out of your references without the use of such an engine. Currently, Texpad supports three bibliography engine, BibTeX, Biber and BibTeX8. For compiling indices, Texpad currently supports makeindex only, with xindy to follow in a future version. For processing RNW files, Texpad uses R with Sweave or Knitr related packages given as parameters.