XLSX isn’t an “Excel document” — it’s a ZIP archive of XML files. This article breaks down the internals of the format and explains why streaming writes are fundamentally more efficient than the object model when generating large Excel files in PHP.

Generating Excel in PHP looks like a simple task — right up until the file grows to hundreds of thousands of rows and the script hits its memory limit or dies on a timeout. This is an article about the philosophy of FastExcelPhp and the problems this family of libraries solves.

Why do you need FastExcelWriter when the excellent PhpSpreadsheet already exists? Because it is simply better — faster, leaner and more concise.