MathLiveA Web Component for Math Input
TeX Quality Typesetting
TeX is the gold standard for typesetting of mathematical content.
MathLive supports over 800 TeX commands.
You can paste in MathASCII or Latex, and get back those formats or an easy to parse MathJSON object representing an Abstract Syntax Tree of the formula.
A comprehensive API is available and many options are customizable, from you own dictionary of Latex macros, custom inline shortcuts, custom virtual keyboards and more.
Type an equation: use the keyboard to type symbols, arrow keys to navigate.
When done, select the equation, and copy the LaTeX code to another app.
Some symbols get converted automatically. Type pi and it becomes π.