How I Made Python Excel Exports 9x Faster with Rust

How I Made Python Excel Exports 9x Faster with Rust At my day job, I work with systems that handle a lot of data. One recurring pain point: Excel exports . Every time users triggered a large report — hundreds of thousands of rows — the server would spike. CPU pegged, response times tanked, other requests queued up behind one export job. I tried everything. xlsxwriter with constant_memory mode. Background workers. Chunked exports. But the fundamental problem remained: Python is slow at writing millions of cells to Excel. A 1M-row export takes ~52 seconds . That's 52 seconds of CPU time blocking the server. I started researching alternatives in my spare time. That's when I discovered PyO3 — a bridge between Rust and Python — and maturin , which makes building Rust-Python packages dead simple. And I found rust_xlsxwriter — a Rust port of xlsxwriter by the same original author. The pieces clicked. What if I could keep the Python API but move the heavy lifting to Rust? My first prototype wa