Show HN: Parse Excel files in browser using Rust+WASM (100-MB in seconds)

1 StellaMary 3 8/23/2025, 12:15:27 PM shyam20001.github.io ↗

Comments (3)

StellaMary · 6h ago
Parsing .xlsx in JS with libraries like SheetJS often means:

Loading the whole 100 MB file into memory Blocking the main thread Tabs freezing, fans spinning xlsx-lite does it differently:

Streams ZIP entries (no inflate-to-Vec) Async + cooperative yielding — browser paints while parsing Batch-based parsing (rows in chunks) Memory stays flat, UI stays responsive

StellaMary · 6h ago
For reference, my test case: a 40MB XLSX with ~200k rows.

Parsing with this WASM build: ~16ms (on Chrome, M1 Mac).

Parsing with JS (SheetJS): seconds, often >5s, with UI stutter. So the speed difference is very noticeable on big files.

Curious if anyone here has even larger datasets to try!

StellaMary · 7h ago
Give a try and share your feed back..!! Will be sharing for react and vue ASAP.