TL;DR I wrote a super fast Excel file reader called Xsv, check it out! It’s fast and low on memory because it uses a SAX-based XML parser instead of a DOM-based one. Here’s some benchmarks to prove it.
Simple API for XML, or SAX for short is an event-based API, of which development started in December 1997 1. It is an alternative to the well-known Document Object Model, which was developed around the same time 2.